He does have some OCD, and maybe that is part of it, but the core issue really looks like a GI issue of some type. I say this because (sorry) it sounds like bubbles coming from the stomach and is odoress (sorry again).
As far as asking him, well he is minimally verbal with asd, so that is out. We do talk to him and ask him questions, but that is after he starts belching.
So, it is tought to figure things out when you can't communicate with him. That's why I am trying to see if others have dealt with this sx. Thanks for your insight. John L