ASD and aggresion

[seattlerain]

Just wondering if anyone has any advice on this situation...

My nephew is almost 4 and is on the spectrum. He has been verbal for about a year now, but doesn't really know how to talk about his feelings.

When he is around my younger daughter (2) or anyone smaller and younger than him, he is very physically aggressive.  It doesn't matter what she is doing, he will walk up to her and hit, push or kick her.  When he is not around her, he likes to carry her picture around and talk about how much he loves his cousin.  It has gotten to the point where we can't really hang out with their family because it is hard to keep them separated the entire time.  He does just fine with my older daughter (5).

Has anyone had a similar issue?  He goes to ABA therapy, but they don't seem to know what to do.