I can see this causing real trouble for some family friends. Their son is 36, and raising 3 kids by himself. After divorcing his wife, he ended up taking her back, without getting married again.
They live in Mom and Dad's basement. Just with all the problems relating to our friend and his ex we have told them they need to kick them out. But they are too attached to the kids, who aren't any of them related by blood. They will never make them leave, and actually endure mistreatment by the exwife.
I am eager to see how this plays out for them. Dad was an elder. Son faded (quickly and with a stripper), but has never been DF'd. I think they did make Dad step down though.