They'll run for ages with worn out cams, horribly and noisy mind you, but they will run. If the cam has gone the engine will make horrible noises, you'll have heard the symptoms long before it finally croaks.

The only way the valves can bend is if the timing chain has broken. Find out what is actually wrong with it, then decide whether to fix it. At the moment it sounds to me you're being fobbed off with a cock and bull story. If the mechanic isn't yet experienced enough to differentiate between a worn out camshaft, bent valves and a defunct starter motor I'd decline to pay for him acquiring that knowledge in no uncertain terms.


regards


Pete