Hi and welcome to the site. I'm sorry for your grandson's diagnosis. I would like to point out, however, that having a dx allows you to get him the proper treatment. So many people go for a very long time not knowing what is wrong with their child, and they can't offer proper care. My son went 15 years before we finally found his CF.
It was devastating to hear it, and I have never cried so hard in my life. Once I was able to breath again, I started searching and educating myself as much as possible. The more I read, the worse I felt. It was all doom and gloom. Then I found this site. I found people here with CF who are in their 40's 50's and beyond! I found UP-TO-DATE INFORMATION! Most of what you read is so outdated, so be careful. People with CF have to work very hard to stay healthy, but it can be done. There are so many new treatment options now. Yes CF is still not something we can cure, and honestly may never be something we can cure. After all, it is genetic. BUT we can treat it's symptoms and help prevent it's progress.
Your daughter will handle this in her own way. Let her "grieve" for lack of a better word. When she is ready, she can come here for that hope you say she needs. I think we all need hope. It gave me great hope to see CF patients much older than I was originally told my son would live to be. CF presents itself differently in every person. Identical twins with the same mutations can have different clinical outcomes. Tell your daughter that nothing is set in stone, and her baby does not have an expiration date.
You can help by educating yourself too. I believe that knowledge is power. CF care is very time consuming and tiring. There will come a time when she needs a break. If you know how to handle all of your grandson's treatments, you can take him for a day or a night and let her get out. It's easy to get caught up in the CF and miss out on all of the little things that come with a new baby. So the last bit of advice I have for you is to try and just enjoy that baby!
Stacey