I don't think I'd give him a card, but I would say "Happy Birthday" if you see him. Make sure D4 gets him a card and scribbles in it etc.
I have taken to getting myself something for Mother's Day. Even though my D's are 16 and 14 (and yes, I give them money if they ask for me) and the last two years H has acknowledged it with a plant. I try not to count on it and it helps keep my spirts up. This year, I'm thinking of an "ABsolutely Fabulous" marathon