I’m not sure if you’re looking for additional suggestions or not. But one school that seems smaller and more intimate is Muskingum in Ohio. It’s ABET-accredited for general engineering and its PLUS program offers four different levels of service, so you could taper as appropriate for your son (rather than some of the schools that do a lot first year, little the next year, and none the last two years). In case your son’s not quite on that timeline, this may be an option to consider, though depending on his exact engineering interests, a school with more specialized programming might be more appropriate. But the small class sizes might be particularly helpful in getting your son where he wants to go.
ETA: Marshall (WV) is well known for its support services. It’s often associated with autism, but also has services available for those without an ASD diagnosis (see HELP). It’s ABET-accredited in a number of engineering specialties.