Wow, what shocking attitudes. But then, my child was one of those who needed a bone marrow/stem cell transplant to treat her cancer, which was not curable with chemo alone.
This is no way compares to a fun run.
I'd go to the GP and get a note or contact his MP.
Every year, people die due to not being able to find a match. I can think of two people I know personally who need a match, one a child, is holding in remission. If she relapses, the likelihood is she will die if no match is found. The other has already relapsed. He needs a donor or he will definitely die. He is 24.
Research is continuing, to make this process more efficient for everyone, but until then, this is how it has to be done.
Saving someone's life, directly, deserves a little sympathy, at the least.