Child can't stop burping

I am looking for some help for my 6 yr. old son. I have put him on the "specific carbohydrate diet" for gastrointestinal issues.

A year ago, he started having the non-stop burping. I first took out all dairy, and then eventually gluten. The burping did go away for many months, and then would come and go. He had a mild yeast overgrowth, and I think eating all of the Gluten-free casein free starches, flours, etc. only increased his yeast and bacteria. Anyhow, with this diet (1.5 months now) we've seen a lot of die-off, and finally improved behaviors, but the die-off still comes and goes (as I increase probiotics, sac. boulardii, etc.) He takes enzymes also, but a low amount. Just an FYI - this diet removes ALL starches and sugars (except some honey).

He still tends to have a distended belly, and often has this non-stop burping problem. Sometimes this also hurts his belly, and it's most common in the evenings.

I think he may have some fecal compaction? His bm's tend to be "snaky" (not quite pencil thin, but I still think too thin). They are a light brown always, and sometimes fluffy (the yeast die-off). I am thinking of doing a series of enemas - just warm distilled water?

He does eat a lot of fruits (all baked right now except bananas - per the diet regulations), eggs, and pecan butter. 1/2 avocado per day, cauliflower. He eats very little meat, and not much in the way of vegetables (believe me - we have and still do work on that - truth is, he is doing better than ever now).

Thanks for any help,
Christine