I never told my son, I would just tell him he needed extra help. I always emphasized he was capable of doing anything, or that it was ok to need extra help. The reason my husband and I never told him, because we didn't want him using it as a crutch or excuse. One day he finally asked, at age 18 and I told him. Now, when he tries to use autism to make excuses, I tell him, nice try, but isn't
gonna work. Lol, I know him so well, he's great!
Main thing, tell him when you want, there's no specific time. I waited because I found no reason to do so, it needed to make sense.

These are all labels that will help you to access the right services for him. It sounds like you have good, open communication with him, but you know that he has a lot of anxiety around this so it’s very important the way in which you deliver news to him. Maybe just explain that he has gone to a new doctor who believes the diagnosis may not be ADHD and may be something else. You can explain that sometimes Drs do not agree on diagnoses. And tell him the diagnoses aren’t super different from each other- the treatment is same in some ways and then some added services for him like the occupational therapy for the new diagnoses from the Dr. He may have both so better to tell him he may have something in addition to ADHD rather than tell him he doesn’t and find out later that he does and have to explain that to him. If you tell him the actual diagnosis label of autism, you can tell him that lots of people from all walks of life have it.

You're welcome.
My son has always known he was different, we would just tell him he needed extra help. I guess after a while he said, wait a minute, what's going on here? Like yourself, I couldn't lie to him.

Thank you. I totally understand your thinking about him possibly using it as an excuse. I thought long about that before telling my son about ADHD. But he knew he was different and he was getting extra help and seeing different providers so when he asked why I did tell him and I think for us, it was a really good thing. I always vowed never to lie to him. Ok, Santa is still real, but the big stuff. For my kiddo, this is working out. I just feel bad that we thought we had the answer and now we have another answer - maybe an additional answer. I know how hard it's been for me to deal with but maybe he'll take it in stride. He so often does.

It's really great to see your cheerful mood. Today was rough - not with my son but with his school. Thank you for the smile!!!

Thank you! You made it make so much sense. :) -deep sigh of relief-