Typically, actors don't get residuals from the shows. It's rare. I'm pretty sure he was paid so much up front in lieu of any residuals. Compare his situation to that of, say, Seinfeld or Ray Romano from Everyone Loves Ray. Those guys are making a fortune from syndication as the exception to the rule.
I'm not saying he won't get residuals, I don't know the details, but it's all with how the contract is drawn, and typically, the more an actor makes per episode, the more they cede on the back end in syndication. I guess I'm saying that I wouldn't be surprised if his income from these shows is pretty insignificant in the grand scheme.
I haven't been paying a lot of attention to his situation, but it's impossible not to hear some things. He might still be on drugs, but I agree with Flea completely. I've seen many manic episodes and he is clearly in need of attention. The entire thing feels like making fun of a kid in a wheelchair to me.