Investors are people like you, they also use these forums and all social networks. The problem is not to find an investor but to be able to offer him a good opportunity to profit from his investments and provide guarantees. For this, a bare idea is not enough, you need to invest your personal money and time in the project and create at least MVP. No one wants to lose money by investing in "promise in words."
But if he does not want to go through all that trouble, he can simply invest in Bitcoin. I am not going to recommend him choosing some sort of ICO or joining IEO, because they are not very beneficial. For any investor, bitcoin should be the first choice. It can return the largest amount of money in the shortest time. He should learn some basics of digital currencies as a whole and understand the future of Bitcoin well.