A really successful fundraiser that we just did for school was to have a photographer do family portraits and donate half the proceeds to us. One mom has coordinated this for our schools for the past 7 years. The photographer is really good - we have one outdoor location, each family prepays and gets one sitting and one shot (they can look at the shot and approve it or try again at the sitting) and a set package (1 8x10, 2 5x7 etc.) for $55. Each sitting is 5 minutes and we book 10 per hour for 8 hours netting us about $2K in profits. It's far and away the best fundraiser we do in terms of people feeling like they're getting something of value, and the photographer offers extra prints and holiday cards for additional amounts.
Anyway...if there is someone in your circle of acquaintances who is a professional portrait photographer this might be something to try to pull together in time for holiday portraits. It makes a good amount of $ with relatively little work and it's just one day.
If you haven't already, you might want to look into Lotsa Helping Hands (LHH). It's a free website where people can sign up for errands to help the family - bringing meals, providing transportation (great for any siblings who might have sports or activities to go to), yard work etc. It's a wonderful way to coordinate volunteers and put those "if there is anything I can do..." sentiments to work in a cohesive way that benefits the family.
Best of luck to your friend's son and his loved ones. Hopefully they'll get some positive news for treatment options soon.