What makes you cry?

Yellowcard - Dear Bobbie
This song really touched me. I can't remember the last time something affected me this way. I do love sad songs and listen to them when I'm in a certain mood (which is often), but usually, the music adapts to my feelings, whereas in this case, my feelings adapted to the song.
Although, this is probably because I learned more about the song – how it was recorded, who was involved, etc. And then I started to imagine things, created a picture, and put myself in the person's shoes. Specifically: the vocalist's grandfather participated in the recording of this song, and you can actually hear him in some parts. He talks about how he met his beloved (presumably his grandmother). I don't know why this is all included, but I assumed that this woman is already dead, and he's reminiscing about those days, or perhaps he's dying and thinking about her before he dies (the song says: "When I die, then I die loving you"). Maybe it's both – she died, and he doesn't have much time left, but before he dies, he wants her to be with him, but she's no longer there, and he's sad.