I would ask him if he has any paper work he may have saved that he wouldn't mind handing over to go with the car. Things like work done etc.
When I bought my car I had bill of sale from original owner to second owner, original dealer window sticker, personalized (vanity) plates from second owner (was supposed to turn them in but they didn't ask for them when I got travel slip). When I met with second owner (1985-2006), I asked her if she had any issues with car and it only had one (loss of drive on highway but didn't know what caused it, just hot it fixed).
Good to know past mechanical history of car and any documents the owner might throw out otherwise.
- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT