how to start a fundraiser for a friend?

[Rogue5]

My roommate's brother, is pretty sick. It's a problem with his heart (honestly I'm not sure the extent of the problem (hard subject to bring up when I see him, I plan on getting more info from my roommate when he gets back), but he's been to surgery a couple times and I don't think it's getting any better, he seemed to be doing well, walking around like a normal 23 year old guy on Friday night, but he had to be rushed to the hospital last night). I have been best friends with my roommate since kindergarten, and friends with his brother since high school.

The thought entered my head tonight that I could try to organize a fund-raiser to ease the financial burden that his family and girlfriend (his girlfriend is awesome, she obviously loves him a great deal) are feeling.

The first thing I thought of was to hold a run/walk (my roommate and I have taken up running pretty hardcore lately, and our hometown has a lot of runners), and get people to pledge $, I was thinking some kind of donation to enter the race, and get people to sponsor you for $/mile or something similar.

but then I figured I would literally run until I collapsed, and I am wondering what kinds of insurance etc. I would need (people dying from heat stroke, getting run over etc...)

also, it seems kind of sketchy if I just get handed a bunch of cash and then am trusted to deliver it...(I'm guessing there needs to be some third party to hold the money)

for a location I was hoping to make a 2-5 mile loop through our hometown, and then people could just run/walk as many laps as they were able. I would have to get permission from the town no doubt, but it's a pretty small town, it's not like we'd be running through Boston...

I obviously would need to discuss all of this with his family and also with him ( I don't see him liking the idea, he is a pretty proud guy, it would have to be done delicately) but I was just wondering if anyone had ever done something similar, and could give me advice. Google just led me to mostly crap about campaign fund raising.

CLIFF NOTES: A friend of mine has some pretty bad heart problems. I was thinking of doing a fundraier run/walk to raise some $ for him and his family. I do not however know anything about doing this and was looking for guidance/advice. (I guess the main thing being liability, insurance etc)

Thank you.