Wonder if he was on dialysis prior (nearly all are), why he's suffering from kidney disease (and what disease), and how long he waited for a donor kidney (some never get a transplant). Mickey Mantle is the classic example of a celebrity organ recipient. He was an alcoholic who never should have gotten one, but did in exchange for being a spokesperson for transplant, then died shortly afterwards.
Getting a transplant is not a cake walk. Donor organs can fail to "take". Complications happen. You now have a foreign object inside of you that the rest of your body is trying to reject, so you're dependent on uber-expensive anti-rejection drugs for the rest of your life. And those drugs make the patient more susceptible to all sorts of infection.
My son (age 6) got two liver transplants 30 years ago but only survived a few months due to complications. I pray it goes better for Stevie.