Dan Akroyd was dx'd with this as a kid. They think Einstein had it. Prolly half the engineers at Boeing have it! If the kid has an obsession let him run with it, well considering
what. There was a kid here in NY that stole a subway train and drove it from one end of the line to another without killing anybody. Turns out he had Asperger's.
I once saw a message board/support forum by and for people with this somewhere on the net. A likeable and eccentric crew.
All disorders of the brain run on a continuum, meaning they can range from debilitating through merely inconvenient. Throw in IQ or potential.
Grandma, look for those with expertise. School personnel also run a range--from well-meaning to knowledgeable. Budget is on the back of all principal's minds.
I recommend you look for state chapters of any Asperger's (or Autism) orgs as well as at FAMI (Friends Advocates of the Mentally Ill) and the like. Many people have walked the walk already and your family can be spared much by those who've already been there.
Good Luck!