The way I see it:
Tama really love him as a daughter wwould, but she really feel like she need to love him as a mother to really become the mother of the household instead of the weird in between she thinks se is stuck as. But as they discuted, the only who can cross the line is the fathet, and seeing how horrified the father looked like, I don't it will happen anytime soon, and maybe it will actually serve as a wake up call for him
Worse case scenario, nothing will change because I don't think the author want really bad thing to happen to their main character and them getting together would be one of the most fucked thing to happen in this manga, and in manga with thing like a secret alien invasion going on in the background, that really something (And I still think cat girl is the end game, the author like yuri too much to end tjis like that !). Best case scenario, he fucking grow a spine and change thing for the better.