There's also the option of him possibly seeing Kaeya putting up the ema plaque saying he's a double agent, especially if it's after him getting attached to Diluc and stuff (I can't brain the word I am looking for lmao so we're going with attached) and getting like. sus of Kaeya since he would know by know Kaeya is living with Diluc too. But I don't know if that would go anywhere or not? Hmmmm...