Him hitting well does not justify it. Should he be the DH for all AL games?
If you think 2014 and 2015 are indicative of his actual hitting talent? Then yes, he'd have the 6th best wRC+ on the team. This year he hasn't hit as well though, so including this year, he'd be 8th. In his last 190 ABs he has 11 HRs. That would make him the Royals best home run hitter since Dean Palmer. If you aren't Sys, you would want him in the lineup.