First layer: It's ultimately a person voicing his loyalty to another friend, saying he will always be there for his friend, and despite any arguments, disagreements, fights, etc, that happen between them (which isnt abnormal amongst friends), it doesnt change the fact that friend will be there for the other person for times that it actually matters.
Second layer: The friend also understands that some people change over time, and some people grow up at different rates, and still some people grow away a different direction, thus making a friendship last "until the very end" somewhat difficult. The singer is asking his friend not to forget him, should they grow apart.
Third layer: The friend is acknowledging that friendships can grow apart, and sometimes to the fault of nobody, or simply life happens, feelings change, interests change etc. And he is saying that even if a longterm friendship ends, he will still wish the best for that person, even if that person is no longer in his life
To me, this has several layers of meaning.
First layer: It's ultimately a person voicing his loyalty to another friend, saying he will always be there for his friend, and despite any arguments, disagreements, fights, etc, that happen between them (which isnt abnormal amongst friends), it doesnt change the fact that friend will be there for the other person for times that it actually matters.
Second layer: The friend also understands that some people change over time, and some people grow up at different rates, and still some people grow away a different direction, thus making a friendship last "until the very end" somewhat difficult. The singer is asking his friend not to forget him, should they grow apart.
Third layer: The friend is acknowledging that friendships can grow apart, and sometimes to the fault of nobody, or simply life happens, feelings change, interests change etc. And he is saying that even if a longterm friendship ends, he will still wish the best for that person, even if that person is no longer in his life
[Edit: Misspelled a word]