His transfusion only worked  because he and his sister happened to have the same blood type— something that isn’t guaranteed,  even among close relatives.
미니와 그가 같은 혈액형이었기 때문에 수혈이 효과가 있었던 것이었으니까요. 가까운 친척 간에도 혈액형이 같다고 보장되지는 않습니다.