I would only add that if you do this, I hope he is a friend in deed.

I'm not trying to rain on anyone's parade, but I have personally been screwed, blued and tattooed by both "friends" and relatives over far smaller sums than this, as have my parents.

Just saying, if you do this, make double-sure he will repay you, 'cause if he doesn't Amex is gonna be looking at you, not him, and 200K is a lot of money.