Complex sentence: Kid's father eventually makes his way to the party, demanding to know where Kid is (upstairs helping Sharane get her coat) and, not finding him, Pop vows to wait for him at home.
Split into simpler sentences: Kid's father eventually makes his way to the party, demanding to know where Kid is. When he doesn't spot Kid-Kid is upstairs helping Sharane get her coat-Pop vows to wait for the boy at home.