Ah, yes, I thought it was to do with mental health.
I suppose over the years we have developed coping strategies...
Not really helped by my MIL chipping in every time I raised concerns with "he is just like dh!!" Erm...no he isnt. He cant read and write, he cant sleep without one of us with him at 8.5y and he tip toe walks and hand jerks. sigh.
We got double beds in all bedrooms so we could all get a good nights sleep, for example. Trying to bf ds2 in bed with ds1 squirming next to me wasnt easy!!! 
We let him watch his dvds - which he is pretty obsessive about - more than we should. He tends to watch one over and over for weeks and then switch to another...eg; before xmas it was Victorian Farm, now its Prehistoric Park....next month it will be something else....
He has well over 100 dvds
and probably twice as many books (if I had loads of books he would just learn to read, right???) He has a nintendo dsi (gift from my mum) and does use it occasionally (useful for hospital/docs appts and the waiting) We also have a wii (gift from my mum again) which he also uses occasionally and he got a ps3 for xmas so he could do the driving games - which he is infuriatingly good at!!! Drives dh mad
dh comes in 11th and ds1 comes in 2nd
but we dont use any of them much tbh.
His dvds are his big thing....dinosaurs, trains, top gear, animals etc.....and we do indulge him as a) its educational
and b) he enjoys it and it keeps him happy.
Recently made changes to his diet (which was v limited and v carb heavy) and he is no longer constipated and no longer has bad tummy pains
Also on magnesium and zinc supplements too.
Ds1 is a "good boy" IYKWIM? i.e. no issues at school, no violence, no bad reports etc and IMO that has not helped him...a child with behavioural problems too would have had intervention (and rightly so) long before now.
He is one of the ones that sits at the back and slowly gets further and further behind.
Well. Not any longer.