I vote for illegal.
The rolling to change direction for the waves is no problem and he does that well, and the leech flicks I saw seemed to be from dumping sheet and stopping it quickly which will give an effective pump - once per wave is ok.
However, note how many times the boat rolls to windward without a corresponding change of course to leeward. This background rolling is persistent and naughty.
IJs seem to have an increasingly lax interpretation of Rule 42 though, so I wouldn't be surprised if they allowed this.