there are literally no peer reviewed scientific study demonstrating the pathology of "long covid". In fact, there aren't really any knowledge that there is such as thing as "long covid" in the way we traditionally define diseases
Someone on reddit keeps track of them all:
https://reddit.com/r/LongHaulResearch
also:
Where did you get your information?
I'd suggest just sharing a good paper. Asking somebody where they got their information that something doesn't exist is pointless. You could say the same thing to somebody who doesn't believe unicorns exist; better to just show them a unicorn.