@Kiwibird21 I doubt he gave her the role as teacher, so much as she took it for herself. Given their dynamics, it wouldn’t surprise me if she insisted on educating Abel to become "an heir worthy of the Louvremonte name", and the duke was pressured to give in.
The ML is an incompetent asshole. So he left the education of the kid to the woman who beat him (the ML) s a child thinking she changed her way ? That is idiotic!! If she was great with him as a child then maybe he can have the excuse of "she treated me well so she will treat my son well" but she beat the shit out of her own brother and he expected her to be nice to the kid she publicly hates and expresses her disapproval of ? Was the ML fucking born yesterday ? He is definitely an idiotic garbage parent