Rather, that's a part of his body. If you'll notice, his parents are also wearing ties, despite their shrouded-and-masked appearance and it being incongruous for ALL of them- one would be a coincidence, but all three means there's some other reason. The only reasonable explanation is that their particular species of demon has a large wattle that looks remarkably similar to a tie. He either thinks its a real tie, that all ties are like that, or doesn't know what real humans look like due to Zenon's curse; presumably he figures it out eventually offscreen postgame.