Treasure her, regardless. I know someone who suffered cancer and got better, but then just--like--that loved ones died in a wreck. We are not promised the next hour. But this is not meant to scare, it is reason to rejoice. You have had some good hours with your mom, days, and years. Recount those blessings, regardless of the cancer threat. And may God add to the blessings.
"Lord, we ask for a heart of hope and not despair. We pray for a closer trust in You. And we pray for miracle and healing in your way and time. In the meantime, like everyone, help the mother and daughter to work on the relationship they do have with the time that is presently at hand. And may You get the glory, through it all, in Jesus' name, amen."
Seriously, I am sorry for the scare and the burden.
I cannot imagine the feelings you experience, nor the pain.
but God is Faithful, no matter the number of our days, length of our years, and what we think of them.
I hope more people reply to you with uplifting words of prayer and encouragement.
God bless you more than you can imagine.
--IDEA