Teachers don't get anywhere near as close to sick children as even the office staff do.
Which is how I ended up with the blasted virus. Checking temperatures of sick children and having to look after them until their parents turned up. I had gloves, alcohol handgel and the ability to clean surfaces, but the sheer numbers of sick children I dealt with meant I got it before the schools were closed.
Looking after a few kids during shutdown is completely different to that and, quite frankly, if that was all I'd ever had to do, I would not only not mind doing it too much, I wouldn't have caught it in the first place. Christ knows how many children I cross infected before I had symptoms. By your father's reckoning, it would be more important that I gave the kids with cancer, the one with a mother who is already on oxygen 24/7, the one whose grandmother lives with them, the one whose little brother has muscular dystrophy, the father with severe asthma or the grandmother with COPD an infection that will tear apart their family because 'it's what I'm paid to do'.
Well, sorry, 'Dad', it is not in my job description to knowingly harm and potentially kill sick children or their family members. It's not what I am paid to do, any more than it is to job of people whose purpose is to save life and prevent suffering to do so.
Add in that these are the people who are dealing with all extremely unwell people at very close range, coughing, choking, vomiting and then the workers in turn are potentially spreading the virus to many, many other extremely ill people who might not have had it beforehand. PPE protects the wearer and everybody around them.
To create a situation where people are effectively conscripted or forced to be responsible for as many deaths, if not more, than they save or at least make the dying process less undignified, painful and terrifying for would be a crime.
So 'Dad' needs to get his head out of his backside and actually think about what 'his' suggestion/opinion actually means.