。
How much she must have struggled with her child's education!
Literal
She [topic-は] child [genitive-の] education [target-に] how-much struggled [emphatic-こと] would-be.
A textbook example of literary exclamatory grammar: どんなに...ことでしょう ('how X, indeed!' / 'how much...!'). どんなに ('how much, to what extent') turns the clause into an open-ended exclamation; ことでしょう closes it with a soft conjectural 'I imagine,' and the whole construction reads as the speaker imagining or sympathetically reflecting on someone else's hardship. The form is more elevated than spoken Japanese — you'd find it in essays, sympathy notes, or narrated reflection — and it carries genuine emotional weight, not just rhetorical flourish.