Well, off the top of my head I would say that any chillul shabbos should be kept private and away from the rest of your kids. If he feels like watching a movie, listening to music, or whatever else he may feel inclined to do, he should do it from the privacy of his own bedroom. As far as meals go, if he decides to show up for one, then kol hakavod, and for as long as he’s at the table he’s as much a part of the family as anyone else. And as for leaving early and staying out late, missing shacharis, and sleeping in, why is that different than any other day?
I mean, to someone who doesn’t feel kedushas shabos, or appreciate it’s gift, it really is no different than any other day of the week. Although you may understand that it’s not, he obviously doesn’t. So as far as he’s concerned, treat it like any other day of the week. You can invite him to participate in whatever the family is doing, but don’t push it too much.