Those sound like cool ideas! I'll just throw down some good go-to guy ideas that I've had awesome success with before.

Blowgun this will turn any aged man into a child again.

Das Horn is awesome cuz hey, who doesn't want to feel like a viking.

These beer openers are so cool. Got one for my dad several holidays ago, he loves it.

Hopefully helped a bit! I know nothing about knife sharpeners either, but if he needs one that's a good idea!