If you search in the disABILITIES! forum you will find some threads that deal with the issue of dialysis on
DCL.
From them and from some quick googling, it looks like DCL is not equipped nor staffed to handle hemodialysis. Some people on home peritoneal dialysis have reported being able to do PD on board, coordinating with DCL special services well in advance.
If hemodialysis is needed, although DCL can't accommodate there are some other cruise lines that can through third party services. See Dialysis At Sea:
https://www.dialysisatsea.com/
ETA: For PD, the patient supplies the equipment, fluids, etc.