TBH not sure how far $100k will go to pay developers to maintain and add features to a site like this, if that's his bankroll he needs to be making money pretty quick off the bat.
I don't know what world you live in but things costs on the Internet are nothing compared to offline businesses. I would be comfortable launching this business with well under $10,000 and so would many others. You do not need $100,000 to start a business online.