only you can answer the question OP. You only have to try and think about how your actions now will make you feel when she's gone, if you think you'll have any regrets then address them now, if you don't, then don't be pressured to do anything for anyone else but yourself.
I had a similar situation with my dad, been NC for a couple of years, he contacted me to say he had cancer, I went to see him and it was actually quite cathartic. Because of how removed from the situation I was, I actually felt like for once in my life, I could be completely honest with him about how I felt about the problems we had and told him exactly how the treatment I received from him and SM made me feel all these years from being a small child, no aggression, no anger just matter of fact. He listened to everything I had to say. He wanted me to deal with his affairs when he died and have any money left over and I said no, I told him to sell all his stuff and enjoy his money while he can because I honestly don't want any of it, I never had. There was no arguing, it was very calm and we left on a note of kind of sad acceptance really. I felt relieved that we'd got all that out in the open and I'd finally said my piece after 25 years of being made to feel utterly powerless, it was like a weight had lifted. I didn't contact him again, I got the phonecall from my stepsister around a year later to say he was in hospital dying, so I went, he was pretty checked out at that point, but I stayed in the hospital for a few days with my SS until he died as I felt no matter what I didn't want him to die alone and I couldn't leave my SS to bear that burden on her own either.
I have absolutely no regrets about my actions throughout, I felt I did the right thing by myself and by my dad by being honest and also being there in the end and by my SS, who didn't deserve to be left holding the bag.
You've worked too hard and come too far to let this ruin your progress, whatever you feel you need to do or don't need to do, only do it for yourself, but you do need to realise that they have no power over you anymore, you don't NEED them to have a successful life and fulfilling relationships, and no matter what they say or do now, it won't ultimately make a difference in your life because you've proved you've got the strength to go it alone, you're a different person now.