My SIL "home schools" her kids, all 6 of them. My oldest nephew is going to be 16 this year. I am very concerned about his progress and sometimes I throw out little "tests". The other day I asked him what 36 / 3 is and he did not know. Also, these kids are isolated on a farm and I worry about thier socialization skills. They do belong to 4-H and some other stuff but imo, it's not enough.
Once, my SIL handed me a shopping list and most of the words were mis-spelled. Now, I'm not a great speller but I'm not attempting to home school anyone. I do not know how or what she's teaching them, there is very little supervision from the outside.
I do not agree with my brother's decision to let my SIL home school thier kids but it is none of my business, really. They have to raise thier children the way THEY see fit. I know when to keep my mouth shut (most of the time).
BFD