Answer:
I am not really good with these stuff... but I will try...
well as Eric is only 4 year old any kind of harsh assessment is out of option..
the solution needs to understanding for a 4 year old boy ...
if we try to teach him that hurting other children is bad it might not be very effective so going too easy isn't gonna be effective either...
it's complicated to solve these problems with children but I guess in this case we should go a Lil strict while trying to make him understand what actions are wrong and also rewarding him for his right actions and decisions he makes....
I know it's not gonna be very helpful but that's what came in my mind so.... I hope it's helpful