[Dimis]

It's complicated... but in a nut-shell, like tenrocca said, if less than 30 years old.... it is a nightmare!!!

Unless the purchase is choosing to either:
a) completely re-engineer the car.
b) just planing on a track car.

Also simply being "titled" over 30years old isn't good enough.
ie: can't build in 2010 and title '65. It wont work!

End of the day... purchase choice if he were to continue to buy.
While it really isn't your problem to advise him of these things, you'd certainly be doing him a favour by advising he looked into it.
After that, your conscience should rest clear.