I switched to vaping to help myself quit smoking because 10 years of guilt over smoking was enough. I imagine you had a similar experience, as have most of us here. I don't know much about your illness and I'm not going to super google educate myself enough to step into the argument, so I'll just say that I'm sorry you have this disease, especially considering the bleak outlook.
I know it's not the same thing, but I'm 33 and when I was 19 I had a heart attack and found that that I have a bad valve on top of it. 2 years later my dad had a heart attack. My mom died when I was 16 from lung cancer. I started smoking around the time my dad had his first of many heart surgeries, stupidly. I figured I was dying my mom was dead and my dad is dying too. He didn't have health ins, hospitals were turning him down for surgery, etc. Anyways, I'm turning 34 next month, something I didn't really plan on doing. My dad just turned 69, and has had a new heart for 4 years now. He had a mechanical heart with battery packs for 2 years prior because his heart finally gave out. He walked around the house connected to an extension cord. I don't know what's in my future, but I'll keep on pushing myself regardless. So basically I've been surrounded by some form of death for over half my life now, whether it was my own or both my parents. You never know what's going to happen, but you have to try to stay occupied and positive about it. What I realized was that we are all going to die, and in the grand scheme of things it doesn't matter if it's tomorrow or in 50 years. We are on a rock with puddles, spinning around a ball of fire, and we have very short lifespans. It absolutely sucks, but whatever time we have is all we have.