help advice please, behaviour and extreme anger out of control,

On sharing: teachers and parents think much of teaching the importance of sharing; this is because sharing is a minimally optional NT bonding process. Your son is not NT, and should not be forced to emulate NT behaviours. When those of us on the spectrum share, we share experiences not objects. I might invite a friend to play a game I am playing and then discuss the game with them and exchange assistance and support; I would not allow someone else to play my game depriving me of it even for a short time.

On winning: NT children find it deeply offensive to lose to an Autistic child (who they believe to be inherantly inferior); and will cheat and change rules and playing conditions to avoid this. It is very frustrating to the Autistic child. Peer adjudicated play can therefor cause conflict.

Your son has every right to enjoy competitive play and the persuit of victory; perhaps an orginised sports club would provide a better venue for such having adult referees who should not act in a discriminatory fashion and who can be challenged if they do so.

On controlling play: NT children refuse any suggestion of leadership from an Autistic child (who they believe to be inferior) often to the extent of ignoring the Autistic childs suggestion and then making it themselves to acclaim seconds later. This frustrates the autistic child, who in responce can become more insistant or just abandon social activity altogether.

You should arrange group play in an enviroment you can observe, identify those children whose dismissive and marginalising behaviour most bothers your son, and remove those bullys from your childs life.

This issue is also visible in the workplace, where persons with Autism are passed over for promotions they would be suitable for even where they are the most senior applicant.

On meltdown control: please try to avoid physically restraining your son. When he has a meltdown incedent, he has been pushed beyond his tolerances, and needs your support, not your opposition. Physical restriant makes you the focus of his anger and gives him something else to struggle against, prolonging the incedent; and further makes you, in the perception of the Autistic child, less of a supporting figure.

Optimally, intervention should be essayed before the point of meltdown (if you dont know the signs look for loudness and hyper active behaviours as markers, which are common, but your son will reveal his rising stress in ways unique to him which you should familiarise yourself with) and in any event be an invitation to vocalise the cause of his distress.

An example might be to remove your son from a group that is causing him problems by soliciting help say, serving drinks and while inside asking "Are they cheating again?" You might be suprised at what your child is able to tell you about the causes of his stress when asked during the experience but before meltdown.

Aside from all the good suggestions above, is he getting much exercise? 

A young relative used to have sleep problems and spectacular meltdowns at that age over similar issues, would probably now be classed as ADHD. Going for very long walks (10 miles or so) was the only thing that calmed him down. His father was a keen runner and I wonder if some people have a higher exercise requirement.

Perhaps he should not be with other children until he can learn to walk away when he is losing control. 3 is still young to be sharing and playing with others. I have written elsewhere about how you can get a child to communicate visually, by seeing themselves as a volcano, likely to errupt and using stickers to show you when the lava is rising up the volcano. This needs some understanding in the child, so I suspect that he is too young. He sounds strong, so may hurt someone.

Perhaps contact with his brother is enough for now. My daughter had meltdowns at that age, when older children came to play, if they felt like it, but ignored her when they had other things to do. I locked the garden gate to stop other children coming in. She was the eldest, so it was easier.