How long do students take grinds and what time of year do they start?

id0ntkn0w

Hi,
My nephew is struggling in one of his subjects but his mum is reluctant to get him grinds as she sees them as too expensive and "doing the teachers work for them". But to me they seem like a totally normal part of secondary school at this stage. Just wondering how I might approach her to rethink her position.
I know when I was in school years ago, students taking grinds were in the minority but in passing, now a days I hear of lots of students needed a bit of extra help?
I guess I'm wondering if she has a point. Are grinds doing the work of teachers for them, and also once a student starts grinds, how long on average will them need them? Is it kind of like extra curricular lessons where people are expected to go every week for the while year? Or could I say to her "Just send him for a month or two and he'll be fine". Perhaps its not my business but I just think her attitude is a bit out of date. Although she didnt go to uni herself, she is very focused on him getting a good education. Surely grinds come part and parcel with this?