Complex sentence: Auntie Momma was originally Donna's Uncle Kevin, and when Donna was younger her parents were never around, so he became she in order to provide Donna with a strong female influence in her life.
Split into simpler sentences: Auntie Momma was originally Donna's Uncle Kevin, and when Donna was younger, her parents were never around. So Uncle Kevin becomes Auntie Momma in order to provide Donna with a strong female influence in her life.