I can see both sides to this. He probably thinks he did you a favor bringing you into this lease. I don't think it is cut-and-dry simply because you both pay the same amount. He was hunting the place before you and you entered into the lease knowing he had a spot. I am an in a big lease and each member gets a permanent stand that is his area. We respected the spots people were hunting before the lease even existed. New members come into the lease knowing the prime spots were taken long ago. However, with a little work you can turn a mediocre spot into a good spot. You deal with the hand fate dealt you. But I see your side too.

This sounds like a losing battle if you pursue it that could lead to hard feelings and family problems. I vote for making "your" side of the lease a better spot or getting out if you can't deal with it. Good luck.