Several thousand DACA applicants have already served in the military with many more on the way. If Congress decided to enact legislation that would legally void that program completely, it will mean the exile of a great many veterans and current military personnel. It will be very interesting to see how they approach this matter. My own feeling is that Congress will exercise restraint owing to the fact that thousands of vets, military personnel, and medical students/practitioners among others will invoke the legal doctrine of substantive and procedural due process (14th Amendment considerations). This will likely tie up the federal courts for years if not decades as this matter must be decided on a case by case basis.
And if Congress doesn't act, those members will met by tens of millions of angry voters in 2018.
Trump got elected President on certain promises, including DACA.
Best thing for Congress to do is... nothing, and just let the program die out.
Some of the DACA will self deport, and the rest will be picked up by ICE.
And since DACA has zero provisions for citizenship, I dont think much of it winds up in court.