$4000 is a joke. Even the repairs are badly done. If you got it for nothing it would still cost a bit to put right. And has someone has already pointed out, it's a Norlin era guitar and although they were not all bad in that period, it was not a good time at Gibson.
On the other hand, if he is giving it away, I'll have it! I don't think it would cost $4000 to get it nice again.