I'm sorry you are dealing with all of this. It must be very difficult. I guess the good thing is you have your dad's side of the family to serve as role models & you clearly understand the difference between the two families. So you can choose to follow in your dad's family's footsteps not in your mom's.

To my mind, being able to see these two examples of how different people live, is no small advantage. I suspect a lot of people simply wander unsuspectingly into trouble not realizing where their lives are heading. And then, once they get there, they look back & wonder how it all happened. You have the insight to be able to avoid that sort of mishap.

I wouldn't concern yourself too much with whether or not you can feel sympathy for your cousin. This may or may not be something that will come to you with time. The important thing is work toward being a good person yourself. It sounds to me as though you're already well on your way.