Your son could be mine. My husband has just been called to be in the Branch presidency, so he thinks it is great to go up on the stand now. In fact on Sunday I gave a talk, of course he followed me, but would not go to his dad, he kept on going to someone else, It made everybody laugh.
When we first moved into this branch they hadn't had kids there for a long time. And basically this branch only has old people. We got a lot of dirty looks when ever any of my kids made a noise. If my District President saw them give us that look, he would stare them down and then go announce how nice it was to hear children once again, as that is a sign of growth.
AS for going out into the foyer, I hold him on my lap and not let him go. He can't have any toys and it gets pretty boring quickly. I ask him if he is ready to go back in and play with his toys nicely and quietly I go back in. it takes some time but he is getting better.
Just don't expect things to happen quickly, it takes time.