Each child is different so it really is hard to say what will work. Our son is PDD-NOS. I have found that a really structured environment works well. Also getting down on his level works also. I just take him to the side get down to his eye level and talk with him in a calming voice. If you explain cause and effect it may work. Also always explain what is going to happen when going out somewhere. This helps with any anxiety. I also have a friend that uses pressure points on the kids she worked with. She advised to just press lightly on there fingers or toes and talk to them in a calming voice. She works with a lot of troubled kids and was able to calm them in this way. I would say join the local Autism groups in the area and ask the other mothers. I have gotten a lot of helpful advice this way and some really good friends. You may also want to check into behavioral therapy just as an option for further help. I hope this helps.

Remove or lessen the components of his environment which are causing the meltdown. If you know that he will be getting in a high stress situation, remove as many stressful components as possible. Talk him through the situation. Let him know how he is likely to react. Come up with other ways to deal with the situation. Make deals with him. Offer rewards when he initiates social interaction. For example, give him more time to do what he likes to do , if he makes a new friend. Drive him to places where he can socialize. Keep trying.

Well, I can tell you what has helped with my meltdowns more than anything else:
A snoezelen room, or at least, a close approximation.

A room he can go to when things get tough that he can control light, temperature, and sound in, is all that is really required (I personally think the real Snoezelen therapy is sponsored by Ikea to get rid of last year's kinesthetic art work more than actually help people- no more than this is required).

My other standard advice to all parents of AC children is- find their obsession. Turn it into a hobby. Then turn that hobby into a money-making business or job. This is the key to not ending up on the street in Portland, OR with beanbag bruises and police ready to take a headshot.