Shawn Sanborn is not sure which high school will accommodate him this fall with his severe epilepsy, or what kind of work he’ll end up doing later in life. But his life has become a bit easier with his new seizure-detecting dog, Sherbert, at his side. Sanborn, 16, was diagnosed with epilepsy about four years ago and has two brain tumors. Two years ago, the family learned about seizure dogs and set about raising the $25,000 needed to get one for Shawn. They had help from the Marshfield and Duxbury communities, friends, yard sales and a generous donor.