Help with Asperger's son aggressive and defiant behaviour

Hello

My 6 year old son was diagnosed with Asperger's in January, we've slowly been coming to terms with the diagnosis. It wasn't a complete surprise. He's always been a stubborn and difficult to manage child, but the last couple of months his behaviour has gotten almost unmanageable.

He has very frequent meltdowns, sometimes we see them coming, sometimes we can't. When they start there is no going back, he will scream, throw things, turn furniture upside down, lash out, kick, hit, spit and scratch and it takes him a long time (30 mins plus) to come out of it. Afterwards, he's always tired and sends more compliant. It's almost like Jekyll and Hyde. The meltdowns and defiance is mostly triggered by refusal to cooperate, "do as he's told" It is almost impossible to discipline him without all hell breaking loose.

We are really struggling cope, we have 2 smaller children, who also suffer. The whole family seems constantly on edge and the relationship with my husband is deteriorating because it too. Does anyone have any advice on how we can get our son to listen to us without him kicking off? Or any useful resources out there?  We really need help.

Thank you for listening