He is suing her for $1.5 million for the kidney or its return:

Batista charged his wife, Dawnell, repaid his gesture by first sleeping with her physical therapist – and then denying him access to their three kids in an increasingly bitter divorce.

Of course this is just a publicity stunt because it’s against the law to exchange money for body parts and the court isn’t going to order a woman to undergo a surgery that would imperil her health.
I can understand the guy’s pain and desire to hit back at his cheating wife and do whatever it takes to gain access to his kids, but he comes across in the article as kind of whiny and self-pitying. If he has as much pride as he says he does in the article, he might have tried another way to gain access to the kids. If I were him, I would find a new lawyer because the current one is pretty incompetent letting him do this.