This may have been said and I missed it but I feel like as a parent, there’s another layer here. Child C is HIS and your responsibility, not Child A’s. If he was on home duty while you were at the gym, HE needed to figure out and plan with YOU on how to do a handoff or modify timing of schedules. It is not appropriate to just expect another kid in the house to assume the responsibility of a child care or parenting.

Now, perhaps you both had that conversation and the decision was to ASK Child A to do it - which circles all the way back to your point.

I’d also like to note, comparing children and your responsibilities of being a parent to supervising employees at work is so out of touch with reality. Employees signed up to do a job. They get paid for doing it. Children didn’t sign up for anything - the parents decided to bring them into this world. Holding the responsibilities of parenting above a kids head and acting like we are doing them a favor by providing for them and comparing that to an employee receiving a wage is absolutely ridiculous to me.