Is Brother's Blood about Heroin?

I know that there is a comparison (throughout the album) about soldiers dying, and we see that with a lot of Kevin's lyrics. But straight up....is Brother's Blood about intravenous drugs?

Whenever I hear the song, that's the imagery that I get.

There are a few other songs that I think allude to this. The live recorded cotton crush has the lyric, "quit spiking your arms."