In retrospect I view that part as an example of "don't hate the player, hate the game." In negotiated deals like this, it's not unusual to represent yourself as the right choice even if the terms you're offering aren't the best. See homebuyer offer letters for a particularly nauseating example. Who knows or really cares whether those parts of the deal are honest?
Maybe the car truly would have been great for his mom.
Lying to a co-worker about why you are buying the car doesn't strike you as sleazy? Is there a degree of misrepresentation where you'd agree, or do you feel that lying can never be sleazy?
Exactly. Maybe the top-level poster says something like "Oh if you're going to clean it and re-sell it for a profit, I'd rather hold out to see if another coworker actually needs the car, because I also like the warm fuzzy feeling of knowing it's helping them.
"Oh, well what if I told you the $500-1000 I think I can get from taking that work off your hands and re-selling it would really help me out"
"That makes sense. Sold"
See how easy this is without the sleaziness of lying?
Maybe the car truly would have been great for his mom.