Maybe have a word with your bridesmaids and ask them to keep an eye on your dad - if he looks a bit lonely, maybe they could have a chat or ask him to dance. That's what your bridesmaids are for!
I wouldn't try to fix him up with a dance partner though, I'm sure if he wants to dance, he can ask someone himself. He might be a bit embarrassed if you try to arrange it for him, and it might come across like you're trying to set him up romantically, even if you're not!
Are you doing a father-daughter dance? That's always nice :)