You do realize the game is broken into tiers right? Each tier prepares you for the next.
M0 offers 437 gear. Which is meant to set you up for m2-…whatever the keystone rank is before the next ilvl bump.
Like LFR gear sets you up for Heroic. Heroic sets you up for Mythic.
Hes below normal dungeon gear and doing content thats about 3 tiers above his ilvl.