I think it's a bad idea to get in the middle of PC matters. It always seems to upset at least one of the players. I think in this scenario, there must be more history to this group dynamic than your're telling us.
Anyway, as a solution, you could always grant the party a wish at some point on down the road that they could use to give the reincarnated PC back his old body (assuming he even wanted to go back).
Anyway, as a solution, you could always grant the party a wish at some point on down the road that they could use to give the reincarnated PC back his old body (assuming he even wanted to go back).