A Jew that's terminally ill R"l, and the only treatment is thru a bone marrow transplant. He has a very special type of blood (this is not a biological question).
So theoretically and Halachicly (if a Bais Din has the needed powers):
Can a Beis Din force another Jews who was found to match that blood type to do the procedure?
If yes, how far can a Bais Din go to force him to do so?
If yes, how painful the procedure should be to so it can not be forced (from a blood test to, say, a kidney transplant)?
What if there are two Jews that have the needed blood type and each one says "force the other one"?
It is worth noting, that we do have numerous examples when the Halachah obligates a Beis Din to force a Jew into performing a positive Mitzvah: marriage, divorce, Tzedakah, Succah and theoretically all others positive Mitzvos.