Seizure in older chin

My 16 year old chin had a really scary seizure this morning. I found him writhing on the floor of his cage, twitching and thrashing. I honestly thought he had fallen and broke his spine because he had no use of his legs at all. I scooped him up and held him crying while I called my fiancé to come help me. After 5 min he was alert but not moving. After 10 he had sat up normally but was lethargic. I put him in a separate cage and by 20 min he was hoping around normally. He is willing to eat a raisin, dust bath, run on the wheel and eat hay, so appears to be functioning normally. It's like nothing happened.

I took him to the vet and he gave him a thorough check up. He said he's in great condition despite his age except for a heart murmur (he's had that for ~4 years I think). The vet said there's not a lot we can do that's not invasive and stressful for an old chin so he suggested waiting and seeing if he seizures again. I was reading about nutritional deficiencys etc causing seizures so I was wondering if maybe he needs supplements at his age? The vet said no, but I was curious what you members thought. I feed oxbow pellets and Tim hay with occasional raisins. I picked up some critical care in case he needs added nutrition.

I don't know I'm kinda of at a loss here , it came out of nowhere. :( and I'm worried and not sure what to do. Any advice?