I could not have dealt with my son's diagnosis if it wasn't for my parents. My husband was completly unsupportive and has never even been to the CF clinic since my son was diagnosed over three years ago. However, my parents have been there from day one. i called the pediatrician to get my son's sweat test results and I was told to go ahead and come to Dr. office to talk, I immediatly knew it was positive. My parents dropped everything, they both left work, and came with me to get the dreaded news. My husband didn't even show up (I'm still a little bitter!) The emotional support given to me by my parents literally saved my life. You don't have to physically be there to provide support--the phone is invaluable! there will be times when the parents want to talk and times when the mere mention of CF will be unbearable. Don't make CF the only focus of conversation, enjoy the milestones he achieves as any other one-year old does.
Visit when you can and when you do, learn how to give his medicine and treatments and let your grandson's parents (is this you daughter or son) have a day off. I love when my parents offer to take over for a day or two!!
I think it's awesome that you have already taken the initiative to educate yourself and to visit this site.