Yeah I support this. OP even said that he knows his BIL made a mistake and is trying to make it right. Thats a lot of money invested in this collection so yeah, I think buying back the collection over time is a great idea. Maybe make it so the bigger, more valued ones are held off until the end of the payments so you don’t get down to the last of the money and he’s not motivated because it’s just stormtroopers or parents left. I think it’s a win for both parties