D.H.
Does he need clothes? If not, how about a piece of jewelry? A plaque? Don't know how old the girls are, but they could do their hands or better yet, get a pic done of them and get him a nice framed copy - just for him that says DAD on it......with maybe a Dad T-Shirt......
You can always find something personalized as well.
Just start listening to things he says, my hubby always leaves some kind of hint, even if it's, wow, that would be nice, but way to much.....I'm not spending that!!!!
Good Luck.