USTA mixed leagues (at least the ones I'm familiar with) don't allow people to partner who have a difference of more than 1.0 rating points. So in 8.0, you can have a 4.0/4.0 pairing, or a 4.5/3.5 pairing, but that's it. 5.0/3.0 is not allowed. He can't play 8.0 mixed, unless it is with a 4.0 partner I guess. We probably shouldn't derail this thread though.