Good post dolejaly I have found this many times and I always ask about brothers and sisters, as older siblings do provoke younger, sometimes a lot younger out of jealousy feelings, but parents want to believe their older children or just deny it happens .The younger bullied ones , wont tell and so it continues ...
I agree, my son now which is 14 had many issues with anger outbursts at a young age, where as I made many trips to the school to pick him up....Unfortunately his brother which is 12 yrs older than him would find ways to provoke his behaviors. Then of course the older ones will always say its the younger one, which in turn which one do you confront?(the one usually that is being complained about,right?)and one thing I did find very helpful in my sons anger outbursts was instead of telling my son to listen to what we or anyone else had to say, let him speak first, let him fully get out what he is upset about(you may not like his tone, or what he says,) but you will find as soon as you allowed him to express his defense or feelings he will be much calmer about a situation leaving a nice conversation with out yelling. Eventually, he will react to things in a calmer way....But,sometimes its the older kids that need the attention for aggravating his behavior...
I am wondering how his older siblings behave towards him, has he learned the behavior he is displaying towards others, do you supervise when he is in the house, he sounds upset and I would say that there is more to the dynamics in the home ...