Well he played Axis right? Probably Wehrmacht? How hard can it be to rank up with that faction...A level 15 Wehrmacht player is probably equivalent to a level 8 Allied player.
That's not how the ladders work. A Level 15 OST player is Level 15 relative to all other OST players. The other four factions don't play into it.
Another thing you need to remember about the ladders is that they work on ELO: it goes up when you win, down when you lose and it tries to match you with opponents of similar ELO.
In a world where you're actually right about any of this the ELO system would simply conclude that all the Wehrmacht players are simply really good and give them progressively harder opponents until their winrate levels out. Unless you're at the top of the ladder you can't blame the faction balance for your defeats: the matchmaker won't let you.