I don’t have a lot but I would have them go to another place to see if they would be willing to do the transplant! Keep going from place to place until you get the answer your looking for! Tell them not to give up !
May God bless your friend! Also pray pray for answers , God is good and he wants to heal your friend, best wishes
You are free to go to whatever transplant center you choose. Just get your nephrologist to send a referral to them. When I was waiting for a transplant I was listed at 2 transplant centers. The 2nd center even sent for my test results from the first center so didn't need to repeat the tests. You can always ask questions when you schedule the appt regarding calcification in arteries from first transplant.
Blessed with a 2nd Kidney Transplant
After transplant - be very careful of your knees
Vaccinations for covid19 done after Transplant: if you got covid19, what were symptoms and outcome
Negative transplant experience 
