I don't see any reason for him to apologize. Sure it was harsh, but so is reality, and in cases like this, it is better to have them face said reality than giving support for stupid ideals and false hopes. On the long run, it's a bigger help to get her through this, than giving continuous false hopes. If Sato can't realize it anytime soon, well that's on her.
@rtrtrt In some cases, High Schoolers has similar outfits to this in manga.