"ADHD - there's a 3.5 year waiting list"

I have been trying to get my teenage son help with his ADHD now for over 2 years, and it’s been an absolute nightmare, I got a letter just over a year ago telling me he has been referred to the neurodevelopment service for children and young people, I call up and ask for an update and was told they're working through 2020 referrals just now and there’s a 3.5 year waiting list…. 

I actually couldn’t believe this and asked the lady to repeat what she has just told me, how can that be right… 

He is struggling and needs help asap 

I feel they have failed my child along with loads of other children, how can they expect you to wait over 3 years for any help of even get diagnosed with this condition, I’ve asked the school to help but there answer was they can’t really do anything because he hasn’t yet been diagnosed with ADHD. At this rate he will be left school by the time he  gets diagnosed, this can’t be right.