Canada

In the news today they said the amount of liver they take for living donations is already so tiny, there's no way they could take more without grave risk to the father and there's no way they can split it and have it still be a viable replacement.

Apparently, they are planning to use it for the twin that is sickest. The other will go on a transplant list. The father doesn't get to decide.

Interestingly, these twins were adopted from Vietnam (they were sick from birth). The parents and medical teams were quite surprised to learn the father was a perfect match considering he isn't a blood relative. Pretty astounding coincidence I think.