The problem that you mention is a urological problem. This is usually dealt with by a urologist. I have no expertise is diseases of the prostate and bladder. If his kidney function has been impacted by the blockage from the prostate and bladder disease, the best thing to do is relieve the blockage and see if the kidney function will return. This may take some time. If his kidneys fail to improve after relief of the blockage, then evaluation for dialysis may be needed. I recommend that you continue consultation with his primary care physician (PCP) and then referral to a nephrologist if his kidney function does not improve.