If someone tells you that there is proof Apollo went to the moon and presents a picture of a mirror NASA said the astronauts left there here is how easy it is to discredit their claims: If their proof is that there are mirrors on the moon, and we know that Apollo went because we can use them to bounce a laser beam off of them, simple show the proof that a mirror is not even needed. Examples of that are:

MIT in 1962 bouncing lasers off the moon with no need for a mirror.

https://mitmuseum.mit.edu/collections/object/GCP-00023974

Russia claimed they can and did send mirrors to the surface of the moon and reflected lasers without the need to send humans to place them.

https://www.scientificamerican.com/podcast/episode/long-lost-lunar-soviet-laser-reflec-10-04-27/#:~:text=In%201970%20the%20Soviet%20Union,the%20reflector%20has%20been%20found. But mostly point out their just a fine example of the Dunning Kruger Effect by explaining that almost everything, like NASA's LRO is continuously bouncing a laser off the surface of the entire moon without the need of a mirror.

https://pgda.gsfc.nasa.gov/products/55 So if they say that there proof is a mirror, but the mirror is not needed, they have no proof. Its not proof. This is how NASA spread the conspiracy theory though. Outdated information, nonsensical proof and knowing the grand majority of people will spread this nonsense like wildfire and dispute any facts that discredit it.