Great song! My ear always goes to the singer--can't get enough of a good singer, and this is a good one.
My ear hears a lot of mid-high freq energy in the mix, which is shared between the rhythm guitar and the singer, especially at about 1:00+.
Have you tried sidechaining a compressor to duck the guitar, just slightly, when the singer's voice is present?
To get even trickier, you could try coupling a slight freq cut in the guitar in the singer's band--about 1200-2400 Hz--to whenever the singer's voice is present.
These are only slight differences I'm talking about, just enough to clear a little freq space around a singer's voice that I really want to hear.