Chris is capable of change, but every external force that he allows to act on him (combined with his own exceptionally poor choices) is dragging him down this death spiral. Finances. I HAVE AUTISM PLEASE LAUGH AT ME. Anime. Trannydom. 14BC and the hoard.... The S.S. Chris-Chan will not change course of its own volition...
When Barb dies, getting the fuck out of that house would be the best possible shot Chris has at change. He'll hate leaving. He'll instinctively, desperately want to stay in his familiar comfort zone, but getting out from under 14Bc would be the best possible outcome for him.
What Chris ideally needs (and obviously this is pure hypothetical, "in a perfect world" spit-balling) is for someone to step in when Barb dies (or preferably set it up beforehand), sell 14Bc, and use the procedes to set up Chris in a small, self-contained unit, with a trust fund or similar paying his rent (and ideally also regular sessions with a decent therapist/counsellor/psychologist which he is somehow compelled/incentivized to attend: give him a $500 annual convention allowance, dependant on attendance or some shit)
If he stays at 14Bc- [1] he'll be alone, in a huge 2 story house full to overflowing with the personal belongings of his dead parents; Chris can barely manage maintaining cleanliness of his room, and him Bob and Barb combined couldn't manage all the shit in that house. Zero chance Chris will be able to manage the hoard alone. [2] The effect on his mental health of being literally surrounded by ungodly amounts of his dead parents shit. Shit which he'll have no clue what to do with. That would be hard for anyone. For someone as ill-equipped and stress-prone as Chris it'll be completely overwhelming. That mess will just get worse and worse til it causes another crisis like the fire[3] He's complained about feeling alone and lonely consistently, forever. Being the only person in a large 2 story house, where he's used to seeing his parents, will turn that 'lonely' dial up to eleven thousand (which would also give him incentive to let someone else move in, to help him feel less lonely- obviously a recipe for disaster; whether the tenant exploits Chris, or Chris tries to impose his landlordly Mayoral powers on the tenant. Either way, highly unlikely to end well) [4] Even supposing the hoard magically disappeared somehow, just maintaining a house that size involves work and organization Chris is unequipped for; rates, property tax, maintainence, structural issues, knowing what to do if a neighbour says "Your tree is gonna fall on my roof" or if there's funny ant-looking things building nests in the wall-space. Where's he going to get the cash if some big-ticket repair springs up, like the foundations slipping or the plumbing shitting itself? that house is just way too much for Chris.
If he leaves 14 Bc when Barb dies- [1] He has a clean slate; not only is the influence of his parents gone, but also the surroundings he associates with all his past behaviour. That may sound trivial, but it's not; it's way harder to start new behaviours if everything around you is the same as ever. [2] No hoard- Chris doesn't have to deal with 20 tons of his dead parent's stuff, and can you imagine how depressing it must be living, surrounded by that shit 24/7? [3] He lives in place that it is within his abilities to maintain. In a 1br unit, even if he he slipped for a while and the place went to shit, it'd be within his capabilities to get it in order in a day or 2 max.
No doubt Chris will want to stay at Branchland, and I can understand why helping him stay there might seem like the best option. But if there was some way to help him get into something smaller, more sustainable, and not chock to the ceiling with crap, that could be a fucking godsend for Chris.