NTA - this is how my maternal parent died too. After she refused to take care of my dad. She REFUSED. So yeah. Maternal parent. Whatever. She prolonged my dad's suffering. He was living in pain for three months on life support. I felt the wall of pain as I walked into his room. I broke through that, and in his last moment of coherence, he told me he was happy to see me, He died three exceedingly long days later, 11 days before his 65th birthday, and two weeks after I told my sister he needed hospice care...he should have died on Christmas Day, but it was fucking MARCH before I could afford to fly out there.
I wish that next-level pain he was going through had not been my last memory of him. It was a horrifying experience. But nope, my mom decided to die on her own terms.
I'm so proud of you. You're not encouraging her to die, you're giving her dignity in not prolonging her death.