After reading what Southpaw said, if the title is not the insurance/registration certificate, I don't have them for either of my trucks, or my trailer. Here in Sask. SGI honors the registration and signed document of sale, so if he has insurance/registration documents, I wouldn't worry about the title.
in the US, there are three docs:
title: MOST important item. it is like the car's birth certificate. you can NOT register a vehicle without one. it is kept in a safe place, NOT in the car.
registration: not required to sell or buy a car, but required to be in car at all times if the vehicle is "on the road". it shows that the car is legally "on the road"... you get a new registration document every time you "put on the road" a new or used vehicle, and you usually have to renew the registration annually or every other year.
insurance certificate: pretty obvious, it also has to be kept in the car at all times (in some but not all states), but it is NOT the same thing as your actual policy which you usually keep in a filing cabinet in your house.
backstepping to my previous post... okay, even IF the seller can't produce any of those three docs, even a service station invoice for a friggin' oil change may at least have the license plate # on it... that would at least be evidence that the car was legitimately his (but i would be extremely suspicious if he could not produce two of the three legal docs).