] Mr. Bennet must have been aware of his wife’s deficiencies by the time Jane had need of education and should have found a governess or taken some responsibility for instruction himself to improve his daughter’s minds.

What I mean above is that when Jane was old enough (a point in time) for some schoolroom instruction, Mr. Bennet should have seen it was done by someone more qualified than his wife. The reason I chose Jane is because she is the oldest and would need instruction first. It was not a dig at Jane or criticism of her in any way. It was however criticism of Mr. Bennet because IMO it is not wise to ask a pig to lay an egg.