When my mom was told she had stage IV NSCLC ( with mets to the liver) The doctor told her she had maybe 6 months with no treatment and maybe a year with treatment. She was 80 yrs old with no other health issues. She did chemo and Tarceva and lived 2.5 yrs and thanks to the Tarceva much of that was good quality time until the 4th line chemo left her exhuasted. When doctors give time frames it is based on stastics and your mother is not a stastic she is a live human being. Only God knows how much time she has left here on earth.
As for a gift the very best gift we gave my mom during her battle was a scrap book that my sister made. She had all 4 of us and any spouses or grandkids that wanted too look for photos and write down things like what we learned from mom, memories of mom, fun times etc then she crafted each beautiful page and made them fun so there were things to be opened and things to be pulled out of envelopes on each page it was a work of art and mom cried when she read it and I know she looked at it often during her battle especially on days when chemo left her wiped out.She showed it to everyone that visited and thanks to my sisters artistic talent most people were amazed with the book. By sharing our feelings in the book I know my mom knew how loved she was and how much we had gotten from having her as our mother and what mom could ask for more then that? So I would suggest a gift from the heart filled with love.
How old are your kids? My nephews who were very close to my mom as she was their daycare when they were little and her home was a safe place for them to go when they needed to get away from each other or their parents as teens were all teens at the time and they knew from day one. I think young kids usually figure out something is wrong as they pick up more then we think so I am not a person that feels they should be kept in the dark. If they were my kids I would tell them ASAP as I think kids handle such things better then most people give them credit for and I think most kids like to be included in life events rather then left guessing why everyone goes quiet when they enter a room.
You are still so new to this shock so give your self time and you will be able to catch your breath. The first few weeks we all live in shock and fear then we start to find our way. Hang in there and use this board even if it is to vent as people here do understand and that will help you in the long run. I will include your mom in my prayers .

Jan Marie