As you are clearly a doctor, you should answer your own question. We're waiting...
Ah no, I am not a doctor, nurse, or studying in the medical field, so I don't really know how donating shit works. I just feel bad for the future kid. Like we don't to be born just for the sole purpose of being a sparepart.
Above your comment already made me loss my brain cells and now this comment made me feel bad for you because you clearly have no empathy either even if that's the only way we should feel bad and parents also feel guilty for the rest of the life because the child was clearly born as a sole purpose for treating his elder brother which I think goes against the morals as a child has no option...
I can't read all that rant without proper punctuation...it gave me a headache.
I feel bad for the second child. Like they are just using him/her for spare parts. Can't they used the fucker's bone marrow instead?? Like they are father-child after all?