Larissa, welcome (though we all wish you didn't have to meet us).
Set the statistics aside. My mom pushed her radiologist for some stats, and the ones he gave her ended up being compiled from the '70s and '80s!
Take it one step at a time. The first thing to do is get your mom into remission.
I know how you feel about distance. My mom is only 40 miles away, but because I have 3 sons (12, almost 4 and almost 2), it can be very hard for me to visit. The worst part is when my kids get colds, because I don't dare expose her to the germs. I do call every day to check in.
Don't let statistics - or even setbacks - scare you. Every patient is an individual. My mom spent 4 days on a ventilator before her diagnosis because her first bronchoscopy made her bleed. But now, she's had such a dramatic response to chemo that her onc is giving her radiation just like a limited case would be.
Take a deep breath and fasten your seat belt. LC can be a wild ride, but there are long-term survivors. Helping your mom take the best care of herself that she can will go a long way.