I have an alt account and used it to experiment with muting all of his alt accounts. It does work, visiting that post with 2700 spam comments (2069 at the time) using my alt, I couldn't see any of the comments left by his 162 alts. I don't think any business would want to be associated with these type of comments, but since he mined some 2 million Steem, it would be impossible to stop him.