DACA's illegal. It can only be made legal by an act of Congress, signed by the President.
I think Trump's right - the Dems have no interest in codifying DACA, and therefore no interest in helping these folks. The Dems do much better politically by watching them suffer with their status undetermined and the threat of deportation hanging over their heads. That's the status that brings in the contributions and allows the Dems to call everyone who insists on the rule of law to be a racist.
800,000 folks hoisted on the petard of political cynicism.