I have also been wondering if steemit would be an effective way to raise funds for charity. My idea is to make the title "FUNDRAISER: (Insert charity or mission here)" and then go on to explain a little about why you are raising money and doing a follow up post to prove the money was in fact donated. You could then make money off of that post from people who appreciate what you did and for using your time to help others. I think it would be a great way to get more people aware of steem and show them we can do great things with this platform. Good luck to you, I hope you raise a good amount of money. Also I'd like to suggest that you actually spend some of the money on items to give to the person and then give the rest in cash.