Hi, does he listen to radio? There are some nice dab portable digital radios around with preset options so he wouldn't have to fiddle around finding the stations he likes.
if he is like my grandfather he would want one thing that is for the family to be together, and go down and have a professional picture done with the hole family. kids grandkid and great grandkids all together that would be the best b-day gift ever.
Hey i havent got any specific ideas but dont get him something he wont like get him something that will make him feel young again from his childhood maybe or even just a family get-together will put a smile on his face hope all goes well