My first 'real' guitar was a thin 1957 Senator, blond with 1 black bar pickup.
Because of the design of the heel, most of these old Hofners will split , the whole neck splitting across the heel parallel to the body. It's very common - it's due to the design, with the bottom end of the fretboard floating across the bodywork. If it hasn't already done this, he's very lucky.
Usually they need to be taken to a decent luthier, have the neck re-fixed to the heel & then the heel reset to get the action right. A bit to pay, but usually well worth it.
I was offered a free Hofner President in decent nick apart from some binding & fretwork about 20 years ago - I had to be honest & told him it was worth a few bob in good nick & suggested he get it to Jimmy Moon, which he did.
I saw it some 6 months later and it was absolutely beautiful and perfectly set up. I was sorry it wasn't mine, but felt I did the right thing. The owner was delighted.
G.