What would cause a 2 yr old to suddenly begin to have seizures?

No actually I can tell right my 2 yr old has had 3 so far since the last time he gt his vaccine shots at 12 mnths shot. His was triggered from too many shots at one time and more so the doctors told he had a seizure because HIS TEMP GOT TOO HIGH TOO FAST and the body goes into a shock first then completely shuts down like a computer. The trick is keep him or her as cool as fast as possible but not too cold or he or she will go into shock. Its scarey I know but I called the ambulance twice and every time they tell mrs.Flanagan youll have to be aware that everytime it happens the best thing to do is keep fluids in him pediasure,water and switch tylenol and motrin to keep the fever down. They also sd the bets way to tell if hes getting really and possible fever into a seizure is to check his palm of his hands and the back of his ears if they feel on fire then hes already too hot and we need t keep him by cool rags on forehead and switching the motrin. Its supposed to be a one time thing with most toddlers but trust Ive researched it a thousand its rare in most cases but it is common that when a child gets sick and fever takes place followed by a seizure its febral seizure u can look it up im sure thats why that is and I found out his dad used to get them when he was younger so i would ask grandma too u never know could have already been signs there youknow does this help please let me know