There does not seem to be any evidence of foul play in the statistics. While the headshot % is high, the kills per minute is extremely low. This is also coupled with the accuracy being extremely low as well, meaning he is is simply doing long distance sniping. At a long distance, you are unable to get a kill with a single bodyshot, so headshots are a must. I imagine he is just countersniping and is getting a kill every 2-4 minutes.
If you're able to get any substantiating footage or recorded gameplay that shows otherwise, we will be happy to review it!