I agree with the others - and Frank is right when he says this is what both you and your OH paid your NI and tax in for all of those years! It is yours by right and you should claim. The forms are complicated - I know as my ex and I filled them in for DLA for H when he was little and having serious problems - so get the AgeUK help that has been suggested.
Harry's helped to pay for the extra help he needed, and you could either spend yours on that, or save it for when you might need it for that! xxxxxxxx