I don't get wtf this guy wants.
First of all, he's acting like some unrequested white knight while his only "merit" is that he fell in love with Nazuna's mother years ago. MC knew Nazuna from months prior his arrival in the story.
Second, even if she can't drink his blood, they can talk about it and there is an easy solution in drinking other people's blood, like the one glasses guy can provide, without even needing to lure people; no need for her to starve to death...more so if you remember that, if MC had succedeed to become a vampire, they'll both be vampire so they need a third party's blood; he was destined to stop being her food reserve one way or the other, so even jealousy would be pointless and out of question.
I'm still convinced that he's already a vampire, and the process is just taking longer to stabilize for whatever reason; but nonetheless this whole fight is pointless af.