I would look for a “transition school” in your area. Transition to college is what it is. There are many colleges & community colleges that have them. I would not go private too expense. Look at Thinkcollege.net
Our son just turned 20 in JAN. He started a transition school last AUG. Only one more year to go, but thank goodness the college we chose offers to help the student if he continues on with his/her degree. He has been doing well, but our mtg “this week” we found out he forgot to login for his online class (how can you forget a class??) he will probably have to take it over.. don’t even get me started!
Our son has Asperger’s very similar to ADHD my very good old boss & friend has a 27 year old daughter with ADHD, we talk all the time. We live in CA and one of our colleges has a “specific college counselor meets with the students with disabilities” you may want to check if any of your colleges have such a program. The student checks in with the counselor depending on what is needed. It seems to work for some students. It is very frustrating, we are in your same shoes. I am not siding with your son, but kids/students w/disabilities have totally different wired brains.
Our son will actually shut totally down if things get too stressful or if everyone is upset. Remember they are always 1-2 years behind developmentally and what we expect out of them will not occur until they are in their late 20’s (per our son’s psychologist).
Don’t give up you are all he has, you need to help him advocate get him on track. It is difficult, but hang in there. You may want to pull him out of college and have him volunteer until you can locate a college that will help him through to learn the skills he needs.