I think this song is about a young friendship that's torn apart by death. The person who has died is trying to comfort their friend left behind, saying that they'll live their life into old age and be happy, without them, and everything will be okay because the next they meet will in the future and they'll have laughter lines from the memories they had already made with them and the ones they continued to make when they lived on. So, ultimately, it is a goodbye but not really because they'll see each other again.
I think this song is about a young friendship that's torn apart by death. The person who has died is trying to comfort their friend left behind, saying that they'll live their life into old age and be happy, without them, and everything will be okay because the next they meet will in the future and they'll have laughter lines from the memories they had already made with them and the ones they continued to make when they lived on. So, ultimately, it is a goodbye but not really because they'll see each other again.