Hi Addysgramie!
We were told by our doctor that CFers are born with regular lungs, it's just that with more infections and with time, lung function can decrease.
Our son was diagnosed shortly after he was born due to an intestinal blockage. My mother-in-law and a number of other friends and relatives learned how to do CPT (chest physiotherapy), learned how to give our son his enzymes and other medications, learned how to use the nebulizer. When one of us goes out of town, my MIL comes to help with CPT. It's nice to have another set of hands. When we first came home from the hospital, DS had lost so much weight that we had to set our alarm and get up at 2 in the morning for an extra feeding. We were exhausted. My parents came to visit and took over the late night feeding so we could get some sleep. Also I HATE asking for help. Sometimes it would be wonderful to come home from work and find that my house was cleaned -- at least the floors swept and scrubbed. My MIL has asked my husband from time to time if there's anything we need and he's suggested dusting or cleaning... We tend to let more things go now that DS has been diagnosed -- tending the flowers, putting away laundry...
One thing that drives me nuts is my own mom. She reads us on everything having to do with CF and tries telling me all about it. I would suggest doing your own research, but maybe not offer suggestions all the time or talk about articles you've read. Let them find their own way...
Also... ENJOY your grandchild! Look past the CF and just play! So many times I see my mother looking at DS with such sad eyes. I just want to yell, PLAY with him. Get down on the floor and play.