My Grandson, Age 7, Lives Outside Seattle. Two Weeks Ago

My grandson, age 7, lives outside Seattle. Two weeks ago he had severe headaches. He was taken to the emergency room, they thought he might be dehydrated, gave IV's he seemed to be OK. At the time a told my daughter to keep in mind her paternal grandmother died from a brain anurism at age 43. We were told at the time that it is hereditary. I know 7 yrs. old might be young to consider this possibility but to keep in mind.
Now two weeks later, he having sever headaches with vomiting. Can you suggest any possibilities?
Beverley Morrison YYYY@YYYY