"Brother" or "sister" includes a half brother or half sister, a stepbrother or stepsister, and a brother or sister by adoption.
"Child" includes a posthumous child, adopted child, stepchild, child born to parents not married to each other, and hanai child acknowledged prior to the personal injury.
"Grandchild" includes a child of an adopted child and a child of a stepchild, but does not include a stepchild of a child.
"Grandparent" includes a parent of a parent by adoption, but does not include a parent of a stepparent, a stepparent of a parent, or a stepparent of a stepparent.
"Parent" includes a stepparent or a parent by adoption.