I have homeschooled and worked with teachers in the PS system. I was hired to teach first grade in a private school and was just smart enough to back out before I damaged anyones critical early years of education. I have taught at the college level (and was kind of awesome, thank you) and IELTS. I am pretty conversant with the education system. In grammar school, teachers deal with a wide variety of subjects but their expertise is teaching and managing a classroom rather than their claim to fame having been that they know the ABCs or how to do simple math. There is more knowledge required in the upper levels, but the things that are being taught are the same things that most parents forgot around the time the midnight feedings started after parenthood. Teachers go to college and learn techniques to deal with different educational styles, how to manage a classroom and sometimes focus on a particular academic subject-but they don't know everything.
I think that a reasonably intelligent person should be able to help a child in a structured educational program when they know the child well if they have any kind of personal discipline. Keeping kids on task is the biggest challenge of teaching, IMO. Or my biggest challenge, anyway. One is a lot easier than 23 or 40.
I did not read everything you wrote, but I just picked up a strong opinion about those without college working with a semi-home schooled student. I wasn't sure where it was coming from. It definitely takes more work and time to assist a home schooled student, but parents work with their children in the PS system all the time and many of these parents do not have the same degrees that teachers do.
Neither one of my parents had the level of schooling that I did by the 9th grade, but the way they failed me was not that they couldn't help me with my homework but that they didn't make sure I was DOING it. They were simply uninvolved (Dad was too busy, mom was too much a JW to care). I think the most critical thing that the son has going for him at this point is not the kind of school that he attends, but that he has a father who gives a damn. How many of us would give our eye teeth for a parent who cared as much as this guy?
My biggest worry is not about the semi home school itself, or the teacher, or the dad-but if mom is going to be dragging this boy off to FS, then he would be better off in the PS system altogether. She will keep him from other kids and he might well be extremely isolated in the congregation. THAT would be a lot more tragic than any minor academic consequences. For a normal family with a child who would grow in that kind of system, I would LOVE the semi home school system. In a JW family, I find it problematic and am conditionally enthusiastic. You or another poster brought up the personality/needs of the child. That is important to consider. And playing at being teacher is NOT what any child needs a parent to do. It takes a lot of committment to home school.