I'd agree that I wouldn't give much over $100. If I were selling, I might try to get $160-200 since people will pay extra for "new" in the box, but I'd take less.
If he keeps it, I'd clean all the moving parts and reapply grease and oil. Make sure the motor bearings and the platter bearing have fresh oil. A new belt is likely needed. It looks like a decent mid fi table of the day.
Cartridge? What's the budget? Maybe an Ortofon Red?