Some people love taking on a project if they can get it for the right price. I spent days scrubbing every surface of the my old camper when I sold it and made sure it needed nothing, so I could get top dollar (which I did).
This thing could take tons of work and only net a couple hundred more in profit. Time has a value too, but it often gets overlooked. I would advertise it honestly, get what he can, and walk away as it will just cost more money to junk it.
I'm sure someone will pay something for it as a hunting camp, restoration project, mobile meth lab, or who knows what else.
