I thought he did in past after reading a past interview, but maybe not. He's definitely on that song though.
As far as mixing goes I feel like Dev does a great job but with so much going on things are gonna get cut. One thing I REALLY wish his music had every once in a while that seems to be completely lacking is some damn bass. Off the top of my head I can't think of any songs that build with bass or have prominent bass lines throughout the song. It's completely buried. Obviously a live performance would allow for things like the drums and bass to breathe more which is why it sucks I won't be able to see him on this US tour anymore since covid-19 decided to headline in every city worldwide. Like all touring musicians he had to cancel his tour which is pretty dire. If you're a big fan and want to hook him, and Ché, Morgan, Keneally, Mike St. Jean,etc. up I would suggest donating a few dollars to the go fund me he just set up.It already hit its "goal" but it's pretty damn modest considering how many people are in the band and have been affected by this.