Hi lynxgal,
I'm sorry to hear what happened to your son I hope he's doing fine now. I'm no Dr. but what you are describing sounds like it could have been a tonic clonic sz. that your son had. I've found that if the water is to hot when I take a shower it will trigger a sz. for me. If your son is at the age of going through puberty that could be a lot of the problem because the hormones in his body would be changing a lot. You might want to ask your son if he had a headache or felt tired after this happened. This always happened to me after a sz. until I had surgery to reduce my sz. The best thing to do is get an e.e.g. and MRI done on your son and this will show any activity (hopefully there's no problems.) Here's wishing you and your son the best of luck and May God Bless You Both!

Sue