My son has been friends for a couple of years with a boy whose older brother has ASD (diagnosis confirmed, SEN provision at school etc). As there is a small age gap between the boys we have play dates with all 3 of them together. Recently the older brother started getting more physical with his brother (never with my son), he gets angry or extremely upset. It affects my son's relationships with his friend and he is reluctant to have more play dates because he "doesn't like the brother". I am very keen to make sure he doesn't break this friendship for that reason alone. What can I say to a 5 year old to explain the situation?