93 year dad having radiation of bladder=hell

my dad has been treated with "bladder polyps/"stones?" prob for about 5 years by an old school doc who he was loyal to- and also my dad is not one to share with his family- so we never knew extent of what was happening. Then during shutdown he began bleeding and having urination issues and told us he would have lithrotrypsy for kidney stones once he could get into doc (???) Anyway I took him to kidney stones zapped only too receive a call from doctor that dad was having a hard time coming of anesthesia from having a tumor removed from his bladder!! What? Then no follow up- Dad got worse and doc said he should have more of tumor removed and he would install "something into his bladder" (BCG) - Dad got mad and left him. He should have had more surgery, but I understand the lack of faithin his doctor. Awful. He did see an oncologist, had a PET scan ( all ok) and started immunotherapy. By this time we were notified of what was happening as we needed to drive him. My mother has curled up into a ball. He finally made appt for second opinion- which took time to get cause of covid. He was really in bad shape and doc ordered surgery and took out more of tumor which was at this point almost blocking ureter. It was muscle invasive. So because of his age and good health otherwise (though he has a pacemaker) he is having a six week course of radiation and monthly immunotherapy. The radiation is burning him up. He wanted to quit, but docs said these last two weeks are crucial. He has gotten quite dememented with all of this and can't understand why he is the same as he was in beginning- having difficulty with urination, peeing all the time. We keep trying to explain the side effects of radiation and he is furious that docs speak to us ( the adult children who are driving him and not to him) They do speak to him, but he can't hear well and can't process. We are grateful to finally have modern medicine aboard. But I don't know how we will get thru two more weeks of radiation. A CT was just done to direct it more specifically. Results this week. Just so nice to find a group of people who may have some understanding of all of this. I feel so awful for him. So mad at past doc, so annoyed that my strong stubborn as hell father hasn't let us in til so late, so sad. I hope by summer he can have some more comfortable days, but I am beginning to wonder if the radiation will have caused too much damage.