This is a song performed by, among others, British band The Hollies and written by Bob Russell and Bobby Scott. For me, it is not clear what the authors' proper inspiration was for the song since there are quite a few stories associated with sayings similar to the song's title. If you'd like to know more about those stories, take this Wikipedia link for your reference:
https://en.wikipedia.org/wiki/He_Ain%27t_Heavy,_He%27s_My_Brother

Anyway, a friend of mine told me a few days ago she is going to make a ceramic sculpture of a girl carying her brother, inspired by this song. So that's when the song came back into my mind and I thought: "I'm going to make up an N40 version of the song."