The answer from AFA is very good. I just want to add that for her sake, if she is really victimized to the point of too much abuse, you may want her to keep some distance for a while. Maybe the children can take care of him for some time. I know some members here took over as caregivers for the parents when the spouse could not cope anymore. His wife's health is also important. So don't take it without a limit. She needs to draw a line. If he goes physically abusive, she will need to stay away from him. There are many options for caring for your FIL, so please make sure his wife is not abused too much.   Regards, Nina