“What do you care if your brother ditches school?” Sheen’s character asks the title character’s sister in “Ferris Bueller’s Day Off.”

“Why should he ditch when everybody else gets to go?” she replies.

“You could ditch.”

“Yeah. I’d get caught!”

He truly seems invulnerable. He is the Anton Chighur of tabloid media, capable of withstanding (or so it seems) any amount of controlled substances as well as public shaming. Sheen’s last flameout was covered more extensively than most foreign wars. His obligatory period of wandering — capped by an apology tour, and declarations that he’s in recovery now — seemed to last about two-and-a-half minutes. Now he seems likely to earn $115 million from “Two and a Half Men” and get a new sitcom, “Anger Management.”

Back in 2000, right before Charlie Sheen started on “Spin City,” I interviewed his father, Martin Sheen, who told me that he’d personally taken his son to jail after his last flameout because he couldn’t bear the thought of enabling him anymore. A Comedy Central roast promo 11 years later started with Charlie Sheen reenacting his dad’s rise from the mud pit at the end of 1979′s “Apocalypse Now,” then revealed that he was in a hot tub with two young women in the backyard of his dad’s house. The punch line was Martin Sheen interrupting the Vietnam fantasy and warning his 46-year old son, “Get inside and wash your face. It’s past your bedtime.”

It was hilarious, provided you didn’t think about what it meant.

There is a depraved magnetism to his antics that it would be dishonest to deny. And without it, “Two and a Half Men” has gone from bad to worthless. It used to be dumb, mean and oddly fascinating; now it’s dumb, colorless and sad. And even the show seems to know it.

Ashton Kutcher’s character, Walden Schmidt, is described in press materials as “a billionaire with a broken heart,” which translates as, “a productive citizen and decent man who is capable of real love.” Walden is first glimpsed on a balcony through the swirling haze of the late Charlie Harper’s freshly spilled ashes, as if he’s Charlie reincarnated. He’s not. The new guy is Warren Buffett-rich but would give it all up just to get back together with the woman who dumped him. He’s fundamentally decent, doesn’t like the taste of alcohol, is uncomfortable flirting with women, and walks all over Charlie’s brother Alan (Jon Cryer) not because he’s a gleefully selfish bastard, but because he just gets carried away sometimes. In other words, he’s the kind of guy who would go through life thinking it was sunshine and lollipops until he came home one day to find his girlfriend in bed with Charlie Harper.

Desperate to make this watered-down Charlie clone interesting, the writers of “Two and a Half Men” give Walden complementary wacky traits: a fondness for walking around naked and a penis the size of a kayak. Lucky onlookers who meditate on Walden’s schlong are struck dumb with awe. Charlie wouldn’t have been impressed. What good is a giant penis to a man with no balls?

Charlie Sheen the human being is, by any objective measure, a miserable, vicious goon. But Charlie Sheen the sitcom star is diabolically watchable — a burned-out satyr amusing himself in an uptight bourgeois world.

I doubt there’s much difference between Charlie Sheen and Charlie Harper, except that Charlie Harper doesn’t terrorize women; he uses them, but only if on some level they want to be used. He has no ambitions. He just wants to get high, get laid, and get away with it. He’s a smirking gangster nihilist, the Lucifer of the Rolling Stones’ “Sympathy for the Devil” playing Oscar Madison in “The Odd Couple.” He slinks through those bright sitcom sets radiating darkness. His existence is a rebuke to the smiley-faced, hug-it-out ethos of network sitcoms. Charlie Harper doesn’t learn, grow or change. He just wanders around getting his rocks off, screwing up, taking advantage of people, and carrying on like a guy who knows that he can get away with anything, and that no matter how much you may think you disapprove of him, deep down you dream of being Charlie Harper for a day.

Charlie’s character was buried in the first part of the episode, in a long funeral scene. We learned that Charlie fell off a subway platform (or was pushed, most likely), got hit by a train and “exploded like a sack of meat.” The roomful of relatives, friends, ex-friends and ex-lovers talked about what a debauched, selfish, rotten, soulless man Charlie was. There were also a couple of jokes about how Charlie had sex with men, too; these were set up with great care, as if the writers thought they were rhetorical knockout blows.

A couple of scenes later, after dreadfully unfunny cameos by former sitcom stars John Stamos (“Full House”) and Jenna Elfman and Thomas Gibson (“Dharma and Greg”), Charlie Harper’s brother Alan (Jon Cryer) sat quietly in the house they once shared and contemplated an urn filled with his brother’s ashes. “Here we are, buddy,” he said. “Just like old times. I’m here talking, and you’re in a bottle ignoring me.”

The interesting thing about that scene — played with unsentimental bluntness by Cryer — was how it resonated. Even as “Two and a Half Men” labored to introduce Sheen’s replacement and make him seem fascinating even though he clearly wasn’t, I found myself thinking about what the deceased Charlie would have had to say about all this. That thought was more entertaining than anything involving Ashton Kutcher and Jon Cryer. At the end of the episode, when Alan exited carrying a hand vacuum that he’d used to sweep up Charlie’s ashes, it occurred to me that he might as well keep the vacuum and periodically talk to it, like Hamlet addressing Yorick’s skull. Even a one-way conversation with an absent Charlie Sheen is likely to be funner than a normal conversation between Jon Cryer and Ashton Kutcher.  

“How much blow can Charlie Sheen do?” joked Jon Lovitz on the roast. “Enough to kill two and a half men!” “You are an incredible medical specimen,” Kate Walsh told him.  “I guess that’s one of the benefits of waking up each morning at the crack of crack.” “He’s the only guy who pulls a knife on a woman who’s already willing to f— him,” Walsh added. (“I’ll drink to that!” chortled fellow roaster Mike Tyson, raising a goblet in toast.) “He’s the reason a dick with cocaine on it is called a Sheenis,” said host Seth McFarlane.” “Charlie, if you’re ‘winning’ then something’s wrong with the f—–g scoreboard,” said Jeff Ross. “The only time your kids get to see you is in reruns.”

That one got a collective gasp/groan from the audience. There were more child custody jokes where that one came from, and a lot more jokes about Sheen abusing and terrorizing women. His wife and the mother of his sons, Brooke Mueller — the one that Sheen supposedly pulled a knife on, and who has had drug problems herself — was in the audience, having fun. “Despite what you read, Charlie is still close to all his exes,”  Lovitz said. “Why, just recently he took Brooke Mueller to Mexico and banged her ass so hard, three balloons of coke fell out. But Charlie’s a gentleman. He put them back in!” Cut to Mueller roaring.

Making a superhuman pariah like Charlie Sheen the target of a roast is like inviting everyone to come take potshots at the Terminator. Sheen, more so than any roastee in memory, seemed unfazed by the zingers; when he finally stood up at the end of the show,  he roasted his roasters — and himself — brilliantly. He ended with a statement that might have played like a heartfelt mea culpa on paper (he talked about how he’d been doing drugs since childhood, and how grateful he was to “still have a family that loves me — that’s why they’re not here tonight”) but that came off as nonchalantly cocky in the delivery.  There was recovery language in there, but it didn’t sound terribly convincing. The overall tone was quietly defiant.

“What I’m saying is, I’m done with ‘the winning,’” he said, putting air quotes around winning, “because I’ve already won. This roast may be over. But I’m Charlie Sheen!” (Whoops from the crowd.) ”And in here” — touching his heart — “in here burns an eternal fire. I just have to remember to keep it away from a crack pipe.”

Charlie Sheen is here to stay. He’s the superstar we want, and maybe deserve.