My mom refuses to quit/try to quit smoking? ideas?

i am 16 years old, a junior in high school. my mom is 52 and has been regularly smoking since she was 18. her sister in law aka my aunt ped away last year due to lung cancer. it left a heartache on my whole family and i, and i cant imagine the pain i would have to go through to lose another someone i love the same way. she is leading a very stressful life right now. she is going through a seperation/divorce with my dad, has a very stressful nursing job which she is always working and doesnt get paid as she should, and also of course me, the teenager. her friends have mostly left on her, her only true friend was my aunt who died of the lung cancer. she knows how bad it is, she doesnt even want to quit though. i ask her "when will you quit" she goes "never" i said "you wanted to quit before you turned 50" she said "yea too much stress i n my life" i told her to find another stress relieving activity like exersize or reading, but she said she hates exercize and has no time to read. she refuses to quit, when i started smoking this past summer she just yelled at me for doing it and called me a dumb person for doing it when she wont even earn the motivation to quit? any ideas? i cant afford to lose my own mom.