Would it be out of place to buy him a new one?

My nephew whom my kids haven't had at our home for a year due to his mother and I not seeing eye to eye came to visit with my in-laws. During his visit he asked my son if he could borrow an Xbox game. He told my kids he bought the game with his birthday money and his mom took the game not long after and sold it. He asked her for either the money to buy something else or another game since it was "his" birthday money that bought it. He said she yelled I don't give a F@$k at him! This is the reason I avoid her. Now I'm upset and hurt for my nephew. I wanted to cry? How could a mother steal from her own child? So I want to buy him a new game. I feel bad for him. She's awful!!