to feel that "don't take it personally" is an inadequate response...

[emkana]

.. by my SIL to her ds being really horrid to my dd2.

Her ds is three, my dd2 is just four, then there's dd1 (6). Nephew adores dd1 and basically feels that dd2 is getting in the way. So when we were visiting he refused to let dd2 come and play in his room (wanted to be alone in there with dd1), at the park he turned on his heel as soon as dd2 approached him in any way, and when dd2 fell off the seesaw and hurt herself he laughed!

I know he's only small, but I couldn't believe it that SIL would do nothing to try and influence his behaviour.

no I agree. not a good way to teach empathy

hm...your ed is older then the 2 of them, why did she not try to involve your yd?

I did talk to dd1 about it and said to her that she should look out for her younger sister, but because dd1 rarely sees her cousin and totally adores him as well she got caught up in playing with him and sort of "forgot" dd2.

Which I think is more excusable than SIL's response...

Once I had talked to her she did make an effort to include dd2, but nephew not keen.

ok, sorry didn't become clear of first post, and no sil response was unacceptable, if that was me I would encourage all children to play together...

I would be upset tbh - I think I would say something to your nephew directly.

FWIW I expect he'll grow out of it.

it is inadequate - I would have stepped in if wither of my children were making someone feel left out.