My nephew (2yrs) seems to hate his nana. He is aggressive towards her, constantly shouts 'no nana' at her, won't play with her, stops playing if she joins in a game, and lavishes all his 'grandparental' love and attention on Granddad. She's a nice person, my DC (2 and 4) get on fine with her. It's really getting nana and DSIL down. Any advice for them from anyone who has experienced the same? Should they ignore it, discipline him, try to find root cause, refer to hv???