Realism is not the order of the day. If Jeph think it would make a good punchline, it's going to happen.
Except that considering how close this particular storyline hits home for Jeph, I doubt there's going to be any real "punchline".
There's a lot that Questionable Content will make jokes about, but there are certain topics that are treated completely seriously and I would wager that Faye's descent into alcoholism is one of them.
You're projecting yourself on to Jeph.
Richard Prior was, among other things, injured in a fire which was related to his drug problem--He described the incident in a show as mixing full fat milk with skim milk and "when I dipped the cookie in, the shit blew up!" He also did bits on all aspects of his drug problems.
A humorist's greatest "weapon" for maintaining advantage over the audience is the realization that anything can be a punch line. Anything.
Whether you get away with it boils down to how you craft the punchline and the awareness of the audience. There are jokes that the majority would have laughed out five years ago, but today seem hurtful and in bad taste.
The end of Fight Club is basically a punchline. Punching up at corporate America as the shining edifices of their power--skyscrapers--topple at the hands of radical idealists. People liked it.
It wouldn't have worked so well if it had come out in 2002 rather than 1999. Something about actual skyscrapers toppling at the hands of radical idealists takes the satisfaction out of the fantasy.
I think Jeph may have even written a rape joke, once.
It's not that I think you're wrong about what he will do. I don't know Jeph's mind at all. But it's mistake to reason that he had a hard time, so he's going to be utterly serious. He's already told jokes about very bad parts of drinking problems. There's no knowing where he draws the line, unless he comes in here and tells us.