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.
Diagnosed with epilepsy and ulcerative colitis in 1979,
Been on meds ever since.