Is her solution just to have him go to school? It's very a slapdick approach to helping him.
What she should be looking into is charities and organisations that specifically cater to people in his situation and helping him sign up to those, as well as helping him find an approach to his schooling that he CAN do. Simply having him go to school, exhausting him further when he needs to work in order to support his siblings, is simply unreasonable and childish.
This is supposed to be an adult who went back in time, right?
(though maybe she does this in the next few chapters, haha)
Burdening children by debts of parents in any shape or form should have no place in modern, developed society.
The mother is the one with the debt (thanks to the father), and she isn't saddling her children with it, but it burdens the entire family regardless.