I've heard you say Kevin's mum before and it does come across as a bit sneery towards parent helpers.
It is a shorthand to illustrate that the level of qualification that the person running the covid testing has is that they are a parent of one of the kids at the school.
Not a medic, nor a trained professional, nor as the government is trying to imply with current headlines, in the military, but literally just someone’s mum. Or dad. And schools will be pretty much taking on anyone willing.
I think people have a right to know that once again kids are being short changed.
That’s not to say that a parent volunteer might not be a fantastic ex-nurse or whatever, but that there’s no requirement for them to be.