I think that's a bare bones oversimplification that if applied widely stands to really pre- and misjudge things.
I went to school, for example, with a couple of Egyptian guys. I asked them one time if they would marry American women or if they would only marry Egyptian women.
"Probably not American, unless she was from a family from a Mediterranean culture, it wouldn't have to be Egyptian," they said.
"Why Mediterranean?" I asked.
"Because a lot of Mediterranean cultures share a lot of the same ideas about home and family and a lot of emphasis on the father having a job that allows the mother to take care of the children," they answered.
"Why that specifically? Do Mediterranean cultures not like women working?"
"No no, nothing like that. But when we were little kids, when we came home from school we had our mother there taking care of us, and we feel like we were better off because of that than the kids who came home and were by themselves all afternoon until the parents came home from work. And we would want our kids to have that too."
Mind you, these were substantially Americanized Egyptian guys... they'd come over at 5 or 6 years old. But they still placed a lot of value on what we would call a "traditional/old-fashioned gender role in the home." And many people, especially with no context or whatever, would broad brush that entire tendency with "sexism" and "wanting to keep women unequal." And I'm sure that judgment does apply to some misogynists in their culture, and to social conservatives or religious fundamentalists, and to many parts of the Middle East or the Mediterranean. I'm also nearly 100% sure these guys weren't lying to me, because they were fluent English speaking Americans born in Egypt who went to school with and formed study groups with men and women all the time. One of their sisters went to med school later, in fact. So I have no reason all of this stemmed from any "illicit" belief that women should be curtailed or not have freedom of choice.
So supposing the topic were "traditional female gender roles in the home", my problem with your reasoning is that it'd be all too easy for us to say: "It's simple. It's a question of whether you value females as equals or not, and if you don't, you're wrong." When that's not only a broadbrushed but also a contextless summary judgment of something that may actually be quite a bit more complex and maintained for a variety of reasons that go beyond what we'd simply rush to label as gender inequality or sexism.
All of that being said? Of course I'm not defending either that women shouldn't be educated with men, or that there is any harmful effect of women being educated alongside men. But equally: you are leaping to the conclusion that this was his belief or the reason for his request.