Complex sentence: Adam Gontier was replaced by My Darkest Days frontman Matt Walst, the brother of bassist Brad Walst, shortly thereafter, who was confirmed as an official member in 2014 and appeared on the band's 2015 album "Human".
Split into simpler sentences: Adam Gontier was replaced by My Darkest Days frontman Matt Walst, the brother of bassist Brad Walst, shortly thereafter. He was confirmed as an official member in 2014 and appeared on the band's 2015 album "Human".