For Mother

sounds like a divorce to me

While I do somewhat agree with the previous commenter about it being about a divorce, I honestly don't 100% agree with that. Hear me out on this.

I personally believe that this song, obviously judging by the title, is definitely a message to his mother, but still not so much. Basically, Dan's saying from his mother's point of view, that he sees her and his father falling out of love after so many years of marriage. They're essentially growing tired of each other, not only as many older married couples do, but also because their love was not true, and they married for reasons other than that they loved each other.

At the end of the song, it goes back to Dan's standpoint in which he is saying "my love is beautiful". Basically saying that he will not make the same mistake his mother made in marrying someone she did not truly love. When he decides to get married, it will be because he truly loves the person, and for no other reason.

That's my interpretation, but who knows what it's really about. Except for Dan, I guess. Ha.