Free loader

There's a loser living in my grandparent's house. He's married to my aunt. They were supposed to move out 3 years after their marriage. 12 years have passed, and they are still living at my grandparent's house. He's a spoiled and lazy free loader. This guy got used to living comfortably at his in-law's house. Yes, they pay half of the expenses, but that's not enough. They're a family of 4, while there's only 2 of my grandparents. It's not supposed to be split, because there are more of them, they use more electricity, food, water, etc. They don't even worry about groceries, etc. because my grandmother handles everything. They know nothing about housework. This loser is very lazy. He doesn't even bring his children to school and his wife to work. He has 2 cars but his wife and children uses our grandparent's cars when they have to go to school and work because he brings his car keys upstairs. The loser doesn't even contribute to the salary of the maid and driver. One time, he borrowed my aunt's car and returned it with no gas. He doesn't buy simple necessities like cotton tips and shampoo because he gets it from my grandmother's room. By the way, they have a 3 car garage, my grandparents have 3 cars, the loser has 2. The loser used to take out my grandparent's cars so that he can park his in. They have money to get their own house, but they won't. He doesn't even socialize with his wife's siblings. He's rude and tactless. And many more. Basically, almost every immediate family member doesn't like him and wants him out. The thing is, whenever we tell our grandma about his antics, she gets mad at us as if we're the ones who's taking advantage of her. She knows that he's wrong, but she won't do anything about it.