Trump in fact gets a great deal out of it in terms of strategy and polling. The “Trump is Hitler” is officially dead and we lose comparatively very little, since Congress was always going to pass DACA protections anyway.
Passing and signing are two separate things. Our Founders thought of that when they formed these two levels of government, houses and executive. Trump does not have to sign it, but he will because he does not care if the DACA promise to his base is broken. The illegals must be appeased and the Democratic base must be grown.