You are right, it should be asexual and aromantic, however, they might have just worded it in a different way and meant that the more relationships his friend had the more he realized he did not have sexual urges and disliked it.
I wasn’t commenting on the story I just wanted to put the definition out there for asexual because a lot of people misunderstand it or don’t know what it means (▰˘◡˘▰)
Oooooo, oki, good thinking, good that you are trying to inform people, I really hope the author was just mistaken about wrote what they meant.
Asexual is not feeling sexual attraction, there’s still romantic attraction there