My 15 year old friend has been having sex for money

So I just found out that one of my friends fucks for money. His mom is a nurse but most of her money goes to the bills so she only gets like 3 things from the grocery store like once a month. His dad works in a tire shop and only makes enough to cover one of the house bills. So my friend, who has recently started showing up to lunch with different fast food & take out meals, told us how he's been getting money to feed himself. He's been having sex with adult women, not even like early 20s but 40+. I asked him if they're aware of his age and he said it's the first thing I tell them I don't lie to anyone. I'm really torn on what to do. I want to tell his parents but he'd probably never talk to me again and what would telling them do because he'll just go hungry again if he has to stop. Idk.