adblockers on chromium-based browsers were severely crippled by manifest V3. they're fine with extenisons (and apparently malware) as long as users can't effectively block their tracking/ads.
Why does that matter if he's not seeing ads. A severely crippled adblocker means that you would see ads during regular usage.
Additionally, Brave a chromium based browser has adblocking built into the browser itself meaning it is not affected by webextention changes and does not require trusting an additional 3rd party.