Offspring returning to family nest after many years away, and with mental health issues sounds like a recipe for disaster. Our adult children are not our responsibility (emotional or financial) in our latter years, they are adults.
I don't suppose there is some way you could sell your house and buy another with a granny annexe for him, then you'd be there for him but not be giving up your own life.
Unused rooms, heat storage and heat transfer
Farage has resigned as an MP for Clacton?

