Complex sentence: Her mother, who herself had had Spike as a teen, provided support, while Shane, whose embarrassed parents wanted him to have nothing to do with the baby, vacillated between wanting to help and avoiding his responsibilities.
Split into simpler sentences: Her mother, who herself had had Spike as a teenager, provided support for her daughter. Shane's parents, however, were embarrassed by the situation and wanted him to have nothing to do with the baby, while Shane himself vacillated between wanting to do the right thing by Spike and avoiding his responsibilities.