Very few movies address cystic fibrosis at all. This is one of the few that does, and does so in an effective fashion. You may think mucus is really "icky" and "gross" but it's a very real part of CF. People show cancer patients vomiting in movies all the time. This is NO different.
As for the sex, it's to illustrate another very real part of CF. Breathing gets in the way of *everything*. Sex goes from being a joy, to being difficult, to being a chore, to being impossible. Being that sex is such a big part of most married couples' lives, it makes sense that it was addressed. I wonder if the director knew someone with CF, because of how well it was handled. The CFer's spouse was constantly worried, and freaked out if his wife was so much as 15 minutes late. Their sex was difficult. Many things in this movie were done well, in regards to the CF.
Not my favorite movie, as I don't much like the way it ended, among other things. But I had to comment about people who complained about the really "icky" mucus. It's real. You don't even have to deal with it. Until your spouse is the one choking on that much mucus, you have no place to call it gross.
