Oh, they care. It's all about control. Hence the Dignitas thing - the final act of control, one way or another. Either she guilts you into compliance or she gets to choose her end.
This is why you feel guilt - you have been conditioned by her to 'enable' her. Fear, Obligation and Guilt (FOG) are the tools of these people.
Also - and as someone with normal human empathy, this can eb hard to get your head around - some of them like to hurt others. And then act like 'oh, I just didn't think!'
I didn't go NC with my mother because I love my Dad. I even became her carer after he died, because of who I am, nothing to do with her. Once she went into a care home I backed right off, and when she was dying I stopped visiting completely.
As a PP mentioned, I had mourned the mother-daughter relationship I would have loved to have had with her, a long time before she died. Her death was nothing other than a relief.
Counselling can help you to discern the difference between appropriate guilt (when you have done something to harm another person) and inappropriate guilt, when you have been made responsible for another person's emotions when you have acted in a perfectly normal way.
Also to discover your boundaries. When a parent doesn't allow you to differentiate from them, you remain enmeshed - having no boundaries between
you and them (hence feeling responsible for their emotions). It keeps you in the state of being a baby - completely under their control.
Dr Karyl McBride's book 'Will I Ever Be Good Enough?' is one I highly recommend.