“Immediate family” of any natural person means any of the following (whether by the full or half blood or by adoption):
(a) The person’s spouse, father, mother, children, brothers, sisters, and grandchildren.
(b) The father, mother, brothers, and sisters of the person’s spouse.
(c) The spouse of a child, brother, or sister of the person.
(Added by Stats. 1990, Ch. 1118, Sec. 6.)