I agree that her father has helped to create this problem. Though his intentions were good to start out with, he should know by now that the situation has gone from bad to worse. Chelsea is not working toward that high school degree, and she clearly isn't capable of the self-discipline that is required to do that on her own. She's constantly complaining about being distracted by everyone and everything, and then she uses that as an excuse to run off for a two hour (or more) study break. I really don't understand what she does with her time. I realize she has a baby, but we see other teen moms managing to hold down at least part time jobs, go to school etc. Chelsea doesn't have to worry about money, bills, housing et. al., and yet she doesn't appear to have the time to study for even a couple of hours a day. Or to keep her clothes on hangers instead of on the floor of her closet.
I understand that her dad is worried about Aubree. In his place, I would be too. But he's not doing her or Chelsea any favors by just giving in to everything Chelsea wants without requiring her to meet her end of the bargain she made with him. It may be too late at this point, but what he really needs to do is give Chelsea a specific date by which she must have her high school degree or he will no longer be paying any of her bills. He should also make it clear that if she wishes to live with Adam, she and Adam are going to have to handle the bills on their own. If Adam is really reformed, he ought to accept that. If he isn't, and heads for the hills again, maybe that will wake Chelsea up. Though I'm not sure it actually would, as she comes across as extremely vacuous and bubble-headed.