Son (7) pushed another kid at school today

Our boy pushed another kid during a game of tag at recess today. He was “it” and not catching anyone, and pushed another kid (who he considers a friend and wants to invite to his birthday party).

He apologized and spoke with the counselor but was crying too hard to fully explain himself, which was also the case when my wife and I spoke with him.

Any dads have any experience with getting their boys to open up?