I was accused once of stealing a hand gun from a new customer that I never even saw too. The customer did not call me, but got the ATF involved. An agent called me and asked me about it. I told my side and evidently they believed me since I never heard from them again. I later found out the man's own son had stolen the gun. I refused of course to ever work for that person again. I put it to the agent like this. I've been in business here for many years. If something like that were proven on me it would totally destroy my business and I'm not risking that to steal anything from anyone. I still to this day don't own a gun although I'm definitely a Second Amendment supporter!
My own sister lost an expensive ring that was missing a good while. We took a trip together in her car to Kentucky. Guess where I found her ring? In the front floor of her car. I'd say either that woman lost or misplaced her ring or someone that was in her house took it. Either way, I would never work for such a person again.
Highly possible the ring doesn’t even exist in the first place. Let the police figure it out.
Going forward he should instruct them to remove all valuables before he arrives. As he does not want to take responsibility for them. This includes rings, that vase that maybe worth something, even the 5 dollars on the end table. They have to move it. I used to put loose things in baggies to move furniture. Not not more. I tell them you clear it off or you move the furniture your choice. This includes their damn clocks. Anyone ever been blamed for them oversleeping because you unplugged their clock? Lol i have many times. Now, they move their own clocks. Not my problem if they forget to reset it.