If its a deal on a jeep I promise there are 10 guys waiting in line to buy it. I assume the scammer chose a jeep because those are emotional impulse purchases and folks are willing to make irrational choices.
I wonder how many people he has the same jeep sold to? Certainly your friend can see through the scam. They do this all the time, offer a too good to be true deal then get deposits from several buyers then run with the money. It's usually a hijacked ad to boot!