Wow, Querty Cat. You are going through a lot at your young age. Yet I am proud of you, and understand your feelings about your mom. I hope you can put together all your feelings, and see you are a good young person above all (because you are) so they ( your feelings) don't cause you too much pain. We don't manage our feelings. They just happen to us.
Perhaps the best service you can do to your mom is taking care of your dad. I bet she would like to be more useful. Maybe she feels guilty, too.
I wish the best for you