Hi @Kate878
Everyone's already offered heaps of good advice.
In this particular instance as a host, I probably would lean towards NOT reviewing and staying silent - hoping that this silence will also have the effect of the guest not reviewing.
If they do leave a negative review, deal with the fallout by leaving a factual professional brief response.
If in any doubt - you could always post your planned response on these boards to get feedback/advice.
Good luck with this.
When I was very little a neighbourhood child drowned like this, so I have empathy for both parties. ( the well had a sealed concrete cover. the child jumped on it as children, including myself, had done for decades, the concrete caved in)
Thank God the uncle was nearby!