|Kate, so sorry to hear about your sister's breast cancer. What a bummer that she won't let you back into her life, especially at a time like this. I am an 'only', no brothers or sisters. Can't imagine turning my back on either one but I hear of it so much it blows my mind.
I have seen how alcohol only worsened mental illness, my mother for example. That's why we parted ways for 12 years and those were years she missed seeing her granddaughter growing up!
Hopefully she comes around before it's too late. I will pray for that to happen.