"It's a great business idea. It will provide you with the freedom to choose which 20 hours of the day you want to work, including weekends."
Here's the reality: He gets huge points for going out and "getting into the game". Who knows? This might be what he loves and ends-up thriving despite the hard work and long hours. There are lots of businesses like that. And, frankly, the fact that they don't scale matters not to a huge percentage of business owners.
The greatest thing about this is that you have a (presumably) young man learning about the realities of business. Succeed or fail, he will be better for it. And, should he choose to move on and do something else he'll be a million times better prepared to make the right decisions and do well. He will succeed, regardless of whether this first venture does or not.