Do you live in the US? If so, usually the pediatrician isn't very good at diagnosing childhood disorders. Also, lots of us traveled a few hours to have evaluations. in my opinion it's hard to know how to treat your child if you aren't sure what the problem is. I'm in a small town area too and we always have to travel. Not fun, but we did get a lot of help. seeing a neuropsychologist and Occupational Therapist (OT) would be a good start.
I'm really sorry about both your family (I had mom who was a PITA too) and your husband's family's refusal to tell you what diagnosis. there have been. It would be so helpful if you could get their cooperation...but ya can't make 'em.
I really do think an evaluation would give you a lot of answers. That isn't the same as a pediatrician's guesswork or a therapist. The testing is intensive and from 8-10 hours and in all areas of function. We learned a lot about our son.