When my next younger brother was diagnosed with leukemia at about age 28, I remember the three of us (other younger brother) going to a facility to be tested for bone marrow compatibility, since that was the best treatment.
Alas there were no close matches in the family, he did not get a transplant, and died 9 years later. Of those years, 8.5 were good, but the ending was awful.
Five years later, Rod Carew the Anaheim baseball player, searched desperately for suitable donors for his daughter, who would also die for lack of a transplant.
BTW Carew is/was a truly good man.
The loss of my brother was devastating to our entire family. He left a 13 year old son, that suffered for lack of a good Dad.