If you're using FreeFrom Android client you can easily block the reply guy by clicking on the three dots on his post and select "block user".
He has multiple accounts so just block them all.
Discussion
He uses a different npub every time he posts
Ooh, I did not notice that.
He kind of failed to post replies on my last post (or I didn't see them) so I thought I had blocked him successfully.
Looks like blocking words is the only way for now... until he changes that too.