At the end (if they are not interested) ask them to keep your business card or contact info in their junk drawer, you never know in 5-20 years from now if they will pull out your info and call.6.

Pay down your credit card debt or collection acts first.

Of course that part depends on your other expenses, credit cards, car payments, and W-2 income.

But other than a lack of knowledge of how to properly construct a buyer broker relationship that protects both parties, he really hasn't done anything scammy. 

In order to wholesale this property you have to have some idea of the rehab cost so you can properly calculate the profit margin that is attractive to a buyer.

That’s why I am saying you aren’t using cap rate properly

Just know them going in so that you can properly budget.

If truly all it needs is a new roof to be complete and ready to sell then a few ideas off the top of my head could be:1)  Borrow the money from friends or family to replace the roof2)  Put the cost of the roof on a no/low interest credit card and pay it off as soon as the house sells3)  Go through a home improvement store (like Home Depot) that offers financing for larger projects like roof replacement4)  Don't replace the roof and just lower your sales price or offer the buyers a credit to fix it themselves after closing

Once again, this takes proper execution. 

I have a gulf access listing in SE Cape Coral that’s in a seasonal rental program and I’ve been giving the current tenants a $25 Publix gift card for each buyer showing.