That may be so, but what you say doesn't answer my question: can they unscrew a lightbulb that is literally falling apart as they unscrew it?
ANSWER:
If the power is off, they likely will remove the glass bulb (one piece), examine the situation and then unscrew the metal bulb base (second piece) and finally, remove any stray material in the (unpowered) socket.
If the power is on, the correct answer is "No, they likely cannot unscrew the bulb. Instead they will likely short the circuit, blow a breaker/fuse and put themselves in a situation where they must call in someone more knowledgeable, (or worse)."
ANSWER:
If the power is off, they likely will remove the glass bulb (one piece), examine the situation and then unscrew the metal bulb base (second piece) and finally, remove any stray material in the (unpowered) socket.
If the power is on, the correct answer is "No, they likely cannot unscrew the bulb. Instead they will likely short the circuit, blow a breaker/fuse and put themselves in a situation where they must call in someone more knowledgeable, (or worse)."