The only way they may find out what the cause is could be to do tests via a 4 or 5 day hospital stay where he has wires attached to his head the same as they use for EEG and monitor him continuously. This normally means staying in bed apart from going to the toilet or at his age they may use a bed pan. They will either sponge wash him or disconnect the cables for him to have a bath. Is his temperature checked every time? Maybe if you do it regularly you may be able to predict if they are temperature induced.
I know of 2 children who had constant seizures. In one of them the MRI showed an inner ear infection. They are too far in to be visible by normal ear examination. One child was nearly 6 and always complained if something was sore or aching. When asked she said she hadn’t had sore ears. The only successful treatment for that was huge dosage of antibiotics as the first lot didn’t eliminate it. The other child was only a baby when he started having them. He actually stopped breathing on a couple of occasions. Both Mothers always put their child in a cool bath to try to reduce the temperature. The Mum of the baby monitored his temperature regularly and as soon as she discovered it was slightly raised bathed him in cool water. His was also an inner ear infection. The children were not known to each other at all.

That’s good that he’s ok now.

Good to know he is ok now, it is very scary when children have convulsions. Both of my older two had them when they were younger as well.

I’m glad that he is ok. Yes, children grow up waaaaay too fast.