Pecs and/or makaton aren't going to work overnight. What motivates him? Is there anything he will focus on that he really wants? For my ds it was chocolate buttons. Does he lead you to objects he wants? Does he come to you if he hurts himself? Does he make noises to express himself? Any non verbal communication at all?
Receptive wise all you can do is keep communicating with him, keep it simple. Use singular words/short phrases for objects he wants and provide him with non verbal cues. For example say cup and hold up his cup. Label objects, read to him whether he pays attention or not. Breaking communication down with pecs and/or makaton can help. When he babbles, make the same noises, see if he notices your copying him. You can't force communication and the last thing you want to do is make it stressful for him.
I can't tell you what will work for your ds but can give you ideas that worked for us.
I wonder if some of your sons energy is sensory energy. My ds doesn't play with toys, doesn't watch tv at all. He is always on the go. Visual aids are very important for him. He needs to know what is happening, where we are going. We do this via pictures.
Ds is never still unless we use techniques to help him focus. His school use a weighted lap pad or weighted shoulder wrap when they are doing sit down work. Ds responds to pressure. He is calmed by tight cuddles, being squished under a therapy ball or peanut. His weighted comes everywhere with us, he also sleeps under one. He is calmed by having his hands and feet rubbed. He will sit and listen to the hum of his bubble tube.
He loves messy play, it certainly channels his energy. He covers himself in shaving foam in the shower. We play with gloop, coloured rice/noodles, water play, normal sand, kinetic sand, orbeez, paint. We have a door way swing inside. A trampoline outside and trampet inside. He loves woodland works, nothing calms him more than a long walk. For us it has been finding things that work for ds and organising the day so that we point him in the direction of things that we know will help. If i left him in a room full of toys with the tv on he would run around the house throwing himself into everything and probably tip the tv over! I hope that makes some sense!
My ds can say a few words (he said his first words last August so it's new for us) but can communicate very effectively. He's the prime example that there's many forms of communication. He uses an ipad with picture based communication software and can make requests in a sentence. He has a severe learning disability alongside autism which has definitely contributed to the severity of his language difficulties. His receptive language is very good now considering he didn't respond to his name till nearly 6 he's doing great. As long as he can communicate i really couldn't care a less how he does it. He's cheeky just like any other kid.
I hope some of this helps you.