I don't think so cause by looking at the timeline or era of the story takes place the story is from 17th to 18th century or victoria something era and the the first use of gender identity or should I say bi gay straight lesbian is being used is 1960 or 1957 to be exact and studied or found out by John William Money
If I say anything wrong here pls guys I'm giving you a freedom to correct if only you type it in a respectable way
In my thread I did discuss this possibility as well, the thing is for pansexual people, they simply feel attracted to the person without really regarding the gender.
In comparison, Aenon struggled to accept that he may very well love Yuri as a man. In this case, although he fell for Yuri for who he is as a person, he did take into account his gender- as a demisexual, I identified with Aenon's struggles and feelings (you could say this is a constant in my life). He only fell for Yuri after a bond was created between the two, he was not simply attracted for the personality.
These are my feelings but he could very well be (I'm not trying to say you're wrong or anything like that btw)! We'll never know unless the author specifies of course :)
Wait y'all genuine question, if he gets attracted by her even though she's a "man" does that make him bi? Or straight?