If we take just a few hypothetical examples from this thread alone, we have young people who are fairly sure (as are their teachers : caregivers) they are ND, but they come from affluent, educated backgrounds, their schools are happy to make adjustments for them, they are confident and happy with who they are. I wouldn’t say they ‘need’ a diagnosis in order to stop them believing negative self thoughts or to give them confidence. They are accepted and supported for who and what they are
DH is in HE and he says the problem then that schools have made accommodations without formal diagnoses but uni policy is they have to them to make accommodation then they get hit with waiting lists.
Though I agree with the general point - we parented the kids we have and worked on their issues and found strategies for them to cope - we watched them and listened to them and worked out what they had problems with and saw what worked - and sometimes with age that changed. It's how my parents operated - and worked for me and my siblings. I didn't need an expert to come in and tell me my eldest struggled with noise - and textures -I saw that for myself and then looked up and tried things to help. So I'm bemused by the posts that parents can't parent property without a detailed diagnosis.
I also won't look for further diagnosis for me - I experienced euphoric vindication with first but workplaces haven't been nice about it. Plus I know where I struggle so even though I think ADHD is very likely in me what the point of pursuing why not just keep finding strategies to cope.
I really tried to get dyslexia diagnosed for eldest two at least - as could see benefits but schools obstructed and when we hit a brick wall we focused on programs at home that could help them.
I really would keep an open mind and if anyone else raises concerns see if you hit criteria to get on waiting list - but at 4 the concerns could just be outgrown but as they get older and gulf between them and peers could get more noticeable and that would be time to get on waiting lists. So see how he copes with transition to school and then as school gets more formal as hit end of key stage 1 and start of key-stage 2 then secondary.