Complex sentence: A dormitory at the University of Massachusetts Amherst bears Grayson's name; however a nearby dormitory "Baker" is probably named after his brother, Hugh Potter Baker, who was president of Massachusetts State College that became the University.
Split into simpler sentences: A dormitory at the University of Massachusetts Amherst bears Grayson's name; however a nearby dormitory "Baker" is named after somebody else. That someone else is probably his brother Hugh Potter Baker who was president of Massachusetts State College that became the University.