Shit, he'll probably just get a free bus ticket courtesy of the city of Charlottesville. That's how a good number of cities deal with that issue.I think up to a certain point you are right about this in regards to the possibility of Chris ending up as a ward of the state but there is a possibility that Chris could end up committed after Barb dies, albeit an unlikely one and prior to the Idea Guys and Chris retreating further into fantasy and delusion, I would have considered the scenario impossible.
If Barb dies and Chris truly and completely snaps past the point of no return, he could end up getting committed and made a ward of the state if (and only if) he gets into enough legal trouble that he gets arrested and is given a psych eval by a professional who isn't his regular shrink, they could recommend him to be put in one of the state-run hospitals in Virginia for these types of cases.
Again, it is not likely but also no longer completely impossible either.
The authorities in Charlottesville and Greene County are more than familiar with him and his antics, and mostly brush off any calls about Chris and Barb (excluding legit major incidents like the fire or The Game Place incident) and I'm sure they dismiss any troll calls about his dimensional merge ramblings because they know of Chris's reputation online and know that Barb keeps him on a short leash (or did up until the Idea Guys) but if Barb dies AND something happens that causes Chris to end up arrested on some misdemeanor or hospitalized due to injury/illness and they take notice of any strange behaviors (relatively speaking) they is a small chance they will involve the courts precisely because he has no next of kin who could make the call themselves once Barb is dead.
But honestly, homelessness is the most likely option if Chris truly does go off the deep end once Barb dies.