What do you say to someone who basically says pics or didnt happen?

I have a friend who whenever I bring up UAPs and how things have been escalating, like the whole Grusch/Congress NHI sitch, he immediately freaks out and says there is no way its true. Last night he said: “If it was true we would know by now and have undeniable proof. If we can take a picture of a dogs butt from space, how do we not have proof?”

He is usually calm/reserved and not so opinionated, but when it comes to this he will absolutely die on the “Its all fake” hill.

Obviously, you can’t convince someone who will deny no matter what. I simply want to know what you could say to get him to consider that it is a possibility.

I consider myself very logical, not prone to fantasy and he is the same. His reaction is almost out of character for him.

TIA