I hear what you're saying, but I think it depends how you parent your teenagers. I'm not a big fan in ruling 15-year-olds with a rod of iron unless there's no other way - mine are diligent about doing chores, cooking, cleaning and so on with no arguments, because they're reasonable human beings and understand that everyone in the family has to pull their weight.
I don't, however, expect them to be blindly obedient to me for the sake of it - they're people too. So when my eldest teen had a really bad day at school, was late home and then discovered his homework was going to take three hours instead of one, he politely asked to be let off some of his chores. Which was fine, because that only happens once in a blue moon. Just as sometimes, I ask the kids to give me extra help and they willingly do.
Without having witnessed what happened or having a better understanding of the family dynamic, I don't think it's fair to vilify the teen unless you believe they should always obey without question in all situations (which I don't, but I suspect you do). So imagine two different possible scenarios.
The 15 year old might have come home late from school knackered and had loads of homework and other chores to do, seen Dad sitting around scrolling on his phone and only sorting dinner for himself. In that case the teen might have been so cheesed off with Dad's uselessness they decided to sort their own stuff out instead of sorting out Dad's failure. If this is part of a bigger pattern, I wouldn't tell my teens off for disobedience as it's sending the message it's their job to compensate for a useless father. That's not the the message I want my kids absorbing, particularly if they become Dads themselves.
Alternatively, Dad might have been doing some urgent jobs before he went out. He might be an equal parent in the relationship, consistently pulling his weight and doing his share of caring for the kids, and the 15 year old might have been lazy and uncooperative. In which case, I agree the teen needs picking up on their failure to do something that was expected of them.
The updates from the OP suggest the first scenario is more likely.