Hey there! What your going through is so difficult. remember that it’s not just your sisters life that has drastically changed but yours and your whole family too, you did not ask for any of this and it is your sisters fault. Saying this, I would find it very hard to fully forgive someone who had done these things, but would also know that it was somewhat necessary to continue a honest relationship with them. I don’t know if your sister is the “I’m sorry” type but a true recognition of the severity of her own actions in relation to the lives of everyone in your family could be a ways of. Guess what I’m saying is can you forgive without the sorry. Guess I’d also say that you are your own person and just cause your sister made bad decisions with her life doesn’t mean you must spend yours cleaning hers up, do not let your family guilt you into doing things you don’t want. Over all I’m so sorry for that you, your sister, her children and your whole family are going through this.