I'd recommend away from doing this … not because it's a bad idea, but basically because he's in a pinch and he doesn't know the space.
Plugins or themes could require a lot of trial and error before finding success, and buyers may not come until later. He needs the cash now, so he should go the sure thing and try to find paying customers directly rather than put things up for sale and wait for results that may never come.
Plugins or themes could require a lot of trial and error before finding success, and buyers may not come until later. He needs the cash now, so he should go the sure thing and try to find paying customers directly rather than put things up for sale and wait for results that may never come.