I'd like to block him 100%. Sure he could use HiveSQL or a chain browser but I don't think he wants to put effort in judging from everything else he does.
This is merely annoying, but imagine if you had a stalker or abuser like some of my female content creator friends.
This is an area where Hive may be lacking as it does not let you stop someone replying to you. The front ends could offer the option to hide everything from muted users. The free speech purists don't like anything to be disallowed.
The screenshot is of an automated reply to me by the way, I know it looks like a post