Nor am I, but what can he do to enforce his rights at that point?

My tenants don't car about his property, and now he has to figure out which tenant violated his rights?

Yet, all these families now have legal rights and protections to live next door to him.

Call the police? Now you are taking a disproportionate amount of taxpayer resources to protect this specific individual's private property rights.

What if it keeps happening? Assign a special task-force to my specific rental property (the one next-door to the parent poster)?