First of, yea, Earth main can remove debuffs, if you see him like a big buff to his whole lineup with the beams coming from below, it means he took off 1 layer of debuff from everyone from his lineup, and probably visual bug occurred. Since he is level 97, I assume you are around same level, and you should already know about most of the main characters specialties/mysteries and what they do.

OR...your control failed and it still created visual bug that made it look like he was chaosed where in fact he wasn't, but you missed the letters "control failed", meaning he had enough control stat points on that character that he was enough lucky to get that control deflected for that turn.