My cousin's 'smart' startup idea is just buying and reselling fuel

My cousin called me yesterday with what he called a 'revolutionary business model'. I'm thinking fintech, agritech, something with actual margins. Bros was explaining how he plans to buy fuel in bulk and resell it at a markup near the airport. I just sat there, phone on speaker, staring at my ceiling.

I asked him what the barrier to entry is. He said 'nothing, that's the beauty of it'. I told him that's not beauty, that's a queue. Every keke driver in Lagos is already doing this with two jerrycans. But he's convinced he's the next Dangote because he bought a yellow plastic tank.

The thing is, I almost didn't say anything because I remembered when I thought building a website for a church was a business. We live and learn. But I still want to know, how do I tell him gently that his 'startup' is just hustling with extra steps?