I have all of the symptoms of hypoglycemia that have been mentioned on this board, and have what feels like a rapid heart rate (is he saying it feels like that, or are you checking it and it really is?). I haven't checked to see if mine really is.
I'm not sure that you need a doctor to tell you he has hypoglycemia. I haven't had any luck there, either. Our 8yo daughter was in a local ER with an obviously broken elbow and she sat there for FOUR hours and no doctor had ever come. I asked the nurse for some juice for our daughter about 3-1/2 hours into the wait, because she (8yo) was pure white, had slumped in the bed, wouldn't respond well to us anymore -- all the things she does when she has what we've self-diagnosed as low blood sugar -- and instead of bringing juice, the nurse brought a blood test, which is all fine and dandy, except that she said, "It's normal. We don't allow food or drinks in the ER." As soon as she left, Dh said, "That's it," and we walked out of that ER, ate pizza and Cokes in the van, and our daughter immediately went back to normal -- talkative, rosy cheeked, sitting up straight -- and we drove to a different ER where they immediately took care of the break in her elbow.
By the way, now that I know better, from learning online, Coke and juice are not the best for hypoglycemia. It's better to avoid sugar and eat some protein, which allows for a slower release of insulin. There is so much to learn! The juice/Coke do give my daughter and I a boost of sudden energy and we feel better, but then we go crashing down, below where we were in the first place.
I don't have any advice on the cleansing. I haven't tried one yet. For us, if we eat every 2-3 hours and eat protein and lower our carb and sugar intake, we do well. I'm going to try the green tea suggestion above, though!