It's been said before, but I think Chris will be able to at least survive. He is capable of shopping, driving, etc., and probably won't completely break down once it happens, lack of empathy and all that (he was fine when Bob died, and he liked him more). However, he will be far more independent than he was before, and that might lead to trouble later on. Barb's a shitty person, but she's also the only controlling factor in his life. Chris will be left entirely to his own devices after she dies, and might, say, fall too far into the gay scene and end up a sex slave to some Buffalo Bill-type for the rest of his days. Which is what Barb thinks will happen, and is completely unreasonable in its own right, but with someone like Chris it's better to be safe than sorry (in the butt).