DD is 11, she's 12 next week. Her cousin is 18. They usually weren't very close, although he did live with us for a few months but DD was very young so doesn't remember.
This summer, DD has wanted to spend a lot of time with him a lot, which has been fine and he doesn't mind, and sometimes nephew, DS (22) and DD go out places etc.
But whenever DD spends time with him alone she comes back upset, apparently he always talks about his dad (DDs uncle that passed away when she was 2 so she doesn't remember him). He also says that MIL hates them all (DD, DS and him) but she loves their other cousins and that she's ‘evil’ which is making DD not want to see her. Since she's being spending more time with him, her attitude has also changed and she's started refusing to do things and answering back etc which could just be a coincidence but I'm not sure!
WIBU to tell DD she can't spend time with him? I really don't know what to do for the best so any advice will be appreciated