The most common transfusion reaction, especially in patients lacking either IgA especially serum IgA, is the development of potentially severe hypersensitivity reactions or anaphylaxis. The most probable culprit is the presence of IgA in the transfused blood, because since the individual lacks IgA, then the IgA in the transfused blood is considered a foreign body triggering an allergic response.
The man couldnt be the dad because there is no B in the mother or father genotype. the dads genotype is ii.