It was my impression that Leader makes decent frames.
http://www.leaderbikeusa.com/ but the website (of the frame that I know) say Leader Bike USA has only been around since 2000, but perhaps Leader has been around before or building longer or your estimate of age is off.
If the exterior paint is in decent shape and the frames actually ride nicely, they seem like singlespeed/fixed gear candidates.
Let the folks know the costs of fixing the bikes up nice (and benefits), and also let them know the costs of a new ride (and benefits). Then let the customer decide.