Buddhism

I think my interpretation has some similar elements to yours so I'm posting it as a reply. I'm not particularly well-versed in Buddhism either, but I wonder if the lantern could be interpreted as an idea, a teaching, or a particular interpretation/lesson.

In this metaphor, the friend has heard a lesson/story/idea from someone else that was really helpful for him personally on the path to enlightenment. He obviously wants to share it with others because it seems really important. But while this idea resonates with him, his friend is blind to it. He's in a different place in his life, so he can't use it in the same way. He still listens to his well-meaning friend and takes it on his journey. But, because it doesn't resonate with him in the same way, he can't use it correctly. Of course a lantern would help you to be safe at night, but if you aren't in a place to use the lantern (lesson) correctly, it's useless to you, personally.

So, in that interpretation, maybe the blind man would represent someone who is not yet ready for that particular lesson? Maybe he'll carry it with him until a later time when he learns to use it in his own way. Maybe he'll learn to hear the sound of the candle so he can still use it for safety at night. Even if he never sees it.