I look after the 2 boys of a very good friend 2 or 3 times a week to help her out with childcare when she is working. One of the boys is very prone to lashing out, due to a condition which means they struggle to control their emotions, with my youngest son bearing the brunt of the attacks. This child is also very overbearing and generally rude and belittling to my son, although my son still says he loves having the boys over to play. I have always tried to tread lightly and give the boy some slack due to his condition. However I feel it is starting to take a toll on my son, he is becoming less confident and increasingly nervous, and has now started lashing out himself at school. If it was anyone else's kids i would end it without hesitation, but as I am doing a favour for my friend I don't know how to broach the subject without risking damaging the friendship. However the situation is becoming steadily worse over time and I am worried that as the children get older and stronger that my son is more at risk from injury as well as the damage to his confidence. Aibu to tell me friend I cannot take them any more?