If this man has been unattached and without a significant other, why not live with his family? Why should he live alone and perhaps be lonely?
Assuming of course he is wanted and there is room and everyone shares equally, I think it's great and what a benefit for the kids to have their grandfather in their lives.
Once a special and mutually exclusive relationship is established with a lady and both of them love each other, it's time to leave the family nest and just be with her.
