The history youtuber TIK history has reported in a video on being plagarized. One of his supporters alerted him and I am alerting you. He was plagarized, as was Armchair historian, as was WWII channel. The videos appear to be straight translations and voiceovers in Portugese.
Take a look and take whatever action you deem appropriate.
(According to TIK the fella doing this is only 16. )