Man knowing how simple that set up is with the bushing, spring and firing pin a rifle must surely have been neglected for the firing pin to seize itself in the bushing and protruding to boot. Especially since the OP's friend had already taken his first shot. I mean, if the firing assembly was loose enough for the hammer to move the firing pin forward, and even if the spring was corroded enough so as it wouldn't bring the pin back to its "rest" position, you would think that closing the action would be sufficient to push it back.
I could see the pin seizing and not allowing the hammer to force it forward. Something in my mind seems amiss!