He was with Stella throughout his formative years and then some; there's no way he didn't learn. You can see it in his treatment of Levon and the way he helped Beth Botrelle purge some of her memories (at a huge cost of pain). So, yeah. I can see him having this sort of conversation with Frannie, no problem, and I can see her willing to listen, because unlike Vecchio, Kowalski wouldn't be yelling and/or mocking her since he isn't her real brother.