Help for my senior aunt and uncle. There grown children with children will not move out. What can I do?

My aunt and uncle allowed their grown son to move in temporarily when he lost his HUD housing. They now have him, his grown son and girlfriend, and 2 minor daughters living with them for a long time. The son gets assistance but spend his money on "questionable women" instead of his children. My uncle is feeding them all and buying the clothes, etc needed for the children. My uncle has high blood pressure and my aunt seems to be depressed. They ask for help and ask for the son to buy food, but they all refuse. They do not know where to turn for help.