I'm not the OP but unfortunately I know many dads like this, including my brother. My nephew was sick last week with the flu (most likely swine flu) and he was still on the bench at football practice last Saturday in the rain. I was LIVID - now it looks like other kids on the team are sick - surprise, surprise. There is just no reasoning with my brother.
I would pull the mom card and keep him home!!! He especially shouldn't be around the other players if he's been running a fever.
Do what's best for your child. As another poster said, this is not the NFL.