No one's going to care enough about Chris to put in jail or even a halfway house. At most they'll probably warehouse him in a motel like Spoony's stalker, the Warthog. At worst, they'll probably release him to his car and send him his tardbux every month.
One thing I wonder about though is Barb's reaction. If she denies everything, says the rape never took place, and refuses to press charges, would it be possible for Chris to return to his house? Chris mentioned using a condom, and there may be no physical proof that intercourse happened. It's hard to imagine that cockroaches like Chris who've bucked the system for so long could actually have any consequences pinned to them. After all, the State of Virginia has been monitoring Chris for years and, other than a few slaps on the wrist and some fines, they've done almost nothing but chat with him and send him on his way, -not that that's ever DONE anything to help him. I know it's super serious this time, but...some people just have a way of slipping through the cracks, especially if they belong to segements of the population that no one gives a shit about.
Another possibility to consider - what if Barb throws Chris under the bus? She may feel shame over what happened, especially if she herself believes it to have been consensual. She may also wish to avoid punishment or a bad reputation. I know it's unlikely, but this is beyond most standards of human decency,and in a dementia-riddled panic, she may just say whatever it takes to make herself look as good as possible.