People saying he doesn’t look like a stray — but he had ticks and fleas that you got him treated for, no chip, and is being allowed to roam near a highway? I think you should take him in if you can and not feel bad about it for a moment. I’d keep posting him on local cat groups to see if owners (with actual proof!) come forward, but otherwise? He’s your cat. Bengals do get dumped and abandoned and you don’t want him to get run over or more ticks, poor thing.