Could be hyperinsulinism. Cancer run in your family? Not saying that's it, but sugar is high octane fuel to cancer. Other's disagree concerning the cancer connection. Most likely is over reaction of pancreas to sugars. Also drinking too much alcohol can drive blood sugar lower. There was this daily drunk who would stop by my get away trailer in Florida when I was visiting, and one day after he'd had two quarts of Cobra, the next day he asked me to check his blood sugar since he'd seen me checking mine. His was 40, so not surprised he was feeling bad. If mine been that low, I'd have passed out for sure, but he obviously still had enough alcohol to keep him standing and supplying alternate fuel. I started buying some lemon lime sugared sodas at Walmart and putting one out each morning so he could start the day off with it.
He died this past year with stage 4 lung cancer, age 54, younger than me by 10 years. Probably brought on by the brown wrapper cigarillos (305's) he smoked at about $3 a pack.
He was an interesting character. I'd found him sleeping in deck swing first time I'd gone there in years. So, eventually I and a neighbor put up a small shed with a mattress for him, and some shelves in it. It's in a small town, so no big city rules to interfere with that.
One day he came back I asked him where his hat was. It was Mother's Day. He'd gone to her grave and sat there "talking" to her for hours and left his favorite hat for her there. I found another one my uncle had left when he died and gave it to him.
I would hire him for odd jobs so he could have some money, like sweep the roof, or rake some leaves, etc. Everyone there knew him as the handy man they'd hire for doing stuff like that. Every day he went looking for some odd job he could do, or help with. He was a bit "********" but not strongly so, and I think his life went downward when his mother had died. He rode a bicycle everywhere, couldn't drive. Other neighbors gave him clothes that would fit when his looked a bit too worn out.
He knew everything that was going on it town, so interesting talking with him when he'd return late evenings. Every day though, he came home with 2 quarts of Cobra malt liquor (strong beer).
I last saw him this past July, and later my neighbor called and told me he'd collapsed and was in a coma in hospital in September. He came out of the coma for about a week, then they discovered the cancer, and in October he died, about a year after that area near Tyndall AFB was hit with Hurricane Michael so badly the previous October.
You can only do so much for some, but have to let them live their life as they see fit, if they aren't willing to change.