Sadly, PCS is real. Definitely. 100%.
Parents will see a dramatic difference in their children; children who may have been previously completely healthy and who have never feined illness in order to get out of school or anything.
Could people all over the globe be inventing a set of symptoms, perhaps for insurance reasons? People who don't have any contact with each other? Why would children join in?
Clearly they wouldn't and any statement that PCS is not real is complete rubbish.

Could some neurologists be incompetent in recognizing PCS?
Yes, they could.
Believe your child.
I think that that is the best thing that a parent can do for a child with this terrible condition, just believe what they say and act accordingly.
It must be an incredibly tough disease for children, especially for children. Parents don't want to be making it worse by disbelieving what their children are saying.
I know that children can sometimes make stuff up. Not in this case.

CS