1. if this is your first investment house, think twice, because there is no easy way back.
2. if you insist to do it. check the numbers three times.
3. if you still think you can make a killing, form a LLC.
4. you should treat 50k as 2nd note, paying interest to your friend.
5. you pay yourself a reasonable management fee for your time.
6. when you sell, split the profit as to article of incorporation. its all about negotiation.