You should bring the contract and paperwork to a title company in the area. Request the title company attorney handle the paperwork. Also, you will need to check if there are any other liens on the property -which the title company can explain to you. Check for back taxes and HOA fees (if applicable). Is the property land or a home??-- You did not mention?- this could involve another issue.
Be sure the person donating money for this charity is protected and that is the number one priority! Please contact a broker or a real estate attorney. They need a tax id number as well.
I would be glad to help you consult with the appropriate parties. Best of luck.