Assuming he KNEW before hand that his clan mate, in another nation, was in the battle to begin with. We need proof, or a confession, that he knew before he joined.
no
it's actually very likely that he did considering what happened, and it doesn't matter if he knew beforehand or not, because when he was already in the battle he already knew that he's blocking teammate and shooting green on green in a battle, which is enough to judge
things like this should not happen