What did Aunt Debbie do?

Aunt Debbie, the sister of Tara's mother Faye, plays an important part in supporting her nieces and nephews. This is despite the fact that Faye has pretty much been ignoring her ever since she married Gene. Debbie's home becomes a relative haven of peace and tranquility for Tyler during his first year at Brigham Young University. Here, without all the chaos and disruption of their usually itinerant lifestyle, Tyler can meet up with Tara and teach her trigonometry.
Later on, Debbie helps out Tara by swearing an affidavit confirming her identity so that she can get a passport to study at Cambridge. Without this help, it's unlikely that Tara would've been able to go abroad. Her parents certainly wouldn't have obliged. Estranged from her mom and dad and most of her siblings, Tara effectively has to create a new family from scratch, and Aunt Debbie comes to be a very important member of that family.