Hi Edith,
To answer your question, it is very common for these gran-mal seizures to start at 19 yrs old. I myself had my first (and only) gran-mal when I was 21. There are several people on this forum that started in their late teens or early 20's.
I can't help you with your "Keppra" question as I am on something else. If it turns out that he has to take meds for the rest of his life, so what ~ as long as his seizures are controlled, he can still lead a perfectly normal and fulfilling life.
I can't help you with your insurance question either as I am from Canada and we all have free health care up here but there are several ppl on this forum that have been in the same situation, hopefully they will read this and post and make some suggestions.
Randy
Diagnosed with epilepsy and ulcerative colitis in 1979,
Hi Edith-
Sorry about your son. It's tough to be a young man and suddenly be faced with this. My epilepsy started when I was 22. I am 46 now and back then there weren't the variety of meds that there are now. I was on Keppra several years back and had to discontinue due to side effects, but some people do very well on it. You have to work closely with his neurologist to get the right drug(s) as it might take more than one try to get something that works. Most everyone on this forum will agree with that!
As far as medical coverage, that one's a tough one. Another option other than regular health insurance is medicaid/state disability. You can always check out your local Soc Security office to see if he qualifies.
Hang in there. Let us know how things are going. HUGS, Glenda 
complex partial seizures since 22