Depends on how old the two of you are. But most of these solicitations are scams. They send you pics then try to blackmail you.

He can charge you, but it is dumb IMO.

That is certainly possible, but it could also be a scam. He should have no further contact with this person and should not speak to the cops...

While maybe not a good practice, it is perfectly legal.

This is a police matter, but likely not grounds for a lawsuit.

While these are defenses that can be asserted, unlikely the charges will simply be dropped. You need to retain local counsel.

Your question is impossible for me to understand. Perhaps rephrase and repost.

We have no idea what the letter is about or why they sent it. But you can sue anyone.

It depends on several factors, including why the repairs weren't done.

Can you be sued? yes. Will they win? Up to a court to decide. But if you don't want to hire lawyers to defend your case, just take it down.