I couldn’t help noticing that the point you made about “you don’t even have to create content, you can find it all online!” didn’t come with a disclaimer about Creative Commons licenses or compensating people if you use their work on your page.
There is no content fairy that leaves free content on the internet for everyone to enjoy. Any content “found online” was created by a human being.
If you have their permission to use it for free to grow and sell a Facebook page, fabulous! If not, your friend may find he receives some invoices in his email inbox for usage rights to the content he’s posted on his page, now that you’ve published his name, the page name and the prices offered for it. I hope he’ll pay up if so – to do otherwise contributes to the devaluation of original work and the inflated valuation of rote, methodical work that adds nothing to the world outside of lining someone’s pockets.