I've done a similar thing, though it was because I was checking out someone at a family wedding. Turned out, they weren't related by blood, only linked by like 3 different marriages. Long story. Hung out for a few months, fooled around a bit, didn't end up going anywhere.He's possibly attracted to Nea in ways he never was to someone with a penis. There are a number of personal and cultural reconsiderations going on inside the MCs head and so this has been more of a gradual learning process than a binary switch option.
Not exactly the same, because trans issues see more spotlight than incest, but there was some internal struggling.