Is he getting stimulated regularly with play and speach etc. I only ask because of a similar parental situation that I know of where because of the parental limitations, the baby simply was not being stimulated or spoken to unless other people were around. once the problem was realised, plans were put in place and the child developed normally.
keep fighting to get something done.
the reason they will not diagnose until much later is that many syndromes and problems have similar symptoms and making the wrong diagnosis is easily done. There are also other traits that come out in older age that make diagnosis easier and more certain.
It was the same 20 years ago. I knew at 18 months that things were noot right, but the health visitor and doctor refused to listen to me., even though I was a very experienced nanny, nursery nurse and a nurse. It pee'd me off, but I just kept records of all events, milestones, observations of his actions etc.
At three years they told me he had a developmental delay to which I responded yes, I know, I have been telling you that for years.
in those days, there was no internet so I would research in the library and I asked for referrals to audiologist (to get a full hearing check as without hearing, speech does not develop in the same way) I asked for an occupational therapist and a speech therapist and they said "no, we'll just keep an eye on it"
I got so mad, I rang the hospital and asked to speak to the paediatric consultant for special needs who I had briefly worked with during my training. He agreed to see us informally and once he met Joe he wrote to my GP asking that Joe be formally referred.
I then got the services I asked for. They also did a full chromosone check which came back clear. Dyslexia and a formal diagnosis was made at 8 of pragmatic semantic disorder, aspbergers, dyslexia and gross motor skills delay.
It was then a very long road. Many hurdles to jump and many frustrations. To cut a very long story short joe is now 21, a qualified lab technician and is an amazing lad.