In case anyone is wondering... bone marrow transplants require getting blasted with chemotherapeutic drugs, some of which can damage the kidneys. After a BMT, the individual has to continue to take immunosuppressant medications, some of which can also damage the kidneys. The ability of a medication to harm the kidneys is its "nephrotoxicity", and he was on a regimen that likely destroyed them.
He is currently caring for himself using, from the sounds of it, peritoneal dialysis. The role of the kidneys is to purify the blood and maintain the appropriate balance of a number of things, including electrolytes. Peritoneal dialysis utilizes the peritoneum (a layer of tissue inside the abdomen) as a membrane, or filter. The tissue is highly vascular, so he essentially surrounds it with fluid with a certain concentration of various substances and lets equilibrium take care of the rest (toxins/excess substances move out of the blood and into the fluid). The fluid is then drained. The process is time consuming, it is difficult, and it requires a lot of resolve. Needless to say, Bobby Elliott is a tough dude.
Kidney transplants, while being major surgeries, are actually done quite frequently these days. He is at increased risk of infection during the procedure due to his current immunosuppression, but I'm sure he will be in good hands. It will also help to prevent his body from rejecting the kidney.
May God bless Bobby Elliott and grant him a speedy recovery.