Your poor boy - yes I can see it must be hard to go through such a change at his age.
If it reassures you, after the initial healing period, we had very little trouble from the 'button'. My son changed to a Mickey button after about 6 months. Try and push for this sooner rather than later, as it is much more unobtrusive than a PEG.
Gosh I didn't know that about children with CF not meeting each other.
Sorry, I don't feel like I'm being very helpful - if you have any questions, ask me though! I do feel for your son and want to say it really won't be that bad, but obviously his worries are real. If his psychologist is good, then hopefully he can work through these with her/him.
Two tips on life with one - I cleaned my son's gastrostomy site every night with saline and tea tree oil and his doctor used to say how amazing it always looked. We had very little infection - maybe 2 or 3 in the 10 years.
I used to change the button every 3 months even though they say 3 - 6. It definitely got more sore to change, and more risk of infection if it was in longer than 4 months.
There is an eye cream which our community paediatric nurses used on overgranulation tissue called Maxitrol - maybe ask about this if it arises.
Also if you get the nutricia Flocare pump, there is a way to stop it beeping (for example in the middle of the night) when the feed is finished - it's on a hidden menu - google it! This made our nights so much easier, especially with other young children waking us up.
Any other questions, just ask xx