OP- I sympathize. We were a two parent working family who did not have the luxury of being able to chauffeur the kids hither and yon during the middle and high school years, when it seemed as though the only way a kid could get into college was to have a full time driver, personal cook, appointment maker, and of course- ATM machine which dispensed twenty dollar bills on demand.
But we made it work with the time and resources we had- and I know you can too.
We learned the hard way that trying to get an uncooperative teacher, administrator, coach, whatever to see things our way only ended in frustration. Lots of folks who end up working in high schools get worn down and end up preserving order and administrative neatness at the expense of student learning.
So I get it, believe me.
But some situations require swallowing hard and just doing what it takes to get the job done. Which in this case- is likely 4 sessions with a tutor- can be a HS senior who loves math and explains things well- to get your son over the hump.
That’s it. Pay the kid the $10 an hour, or a Starbucks gift card as a thank you and move on.
I sense so many other issues you are going to have with this son- that the sooner you put the geometry debacle of 2014 behind you, the better you can focus on what seems to be the bigger picture, i.e. your belief that he lacks maturity, focus, the ability to stay on task without nagging and being supervised, etc.
So you have a lot to sort through before he packs his duffle bag and heads of to college. So get cracking- get him the four hours he’ll need to learn the missing geometry concepts, and move on. If you start to make every single issue about his schooling WW3 you are NOT going to enjoy senior year- which is stressful enough, as you well know.
Dial it back. And if you’re unhappy with the way the HS deals with things like this, bake a tray of cookies next time you have a meeting with the guidance counselor and try starting again.