He is a terrible person and a jerk but it’s understandable that he’d not reply. If I was told to not ever contact someone and was blocked, but then the person unblocked me in order to tell that they want to make sure I leave them alone, I’d not reply. I’d be surprised if I was expected to reply. Why? You told him repeatedly to leave you alone. In general or at events, so why would you want him to reply?

I hope the event went well and you won’t get worried about him and contact him before all subsequent concerts. I think there’s no need to keep communication going. It could literally go on for the next 20 years or how many years he might attend these concerts

It likely strokes his ego that you are even concerned about him attending these concerts (how do you even know?) and contacting him about it. Keep him blocked and don’t pay attention what he’s doing or not doing. Don’t give him the satisfaction