The Constitution grants far fewer powers to the President than they appear to have granted themselves or that have been unconstitutionally delegated to them by congress.
The powers of the president are enumerated in the Constitution. The obligation to execute the laws passed by Congress is both an obligation and an enumerated power. The power to repeal laws or to make laws is not granted to the President.
As an executive he could make a determination that a law is so complicated that he cannot, in his exercise of presidential authority, execute the law faithfully and could exercise his authority to call an extraordinary session of congress and force them to stay in session until they re-write the law so that it is capable of being faithfully executed, or he could demand that if they could not so fix it that they repeal it.
As an aside, the problem with our immigration laws is that no president has ever seen fit to faithfully execute the immigration laws. They are quite adept at faithfully executing the tax laws on citizens, but they seem to look the other way when illegal immigrants cheat on their taxes and steal the identities of taxpayers.
If presidents actually took the oath of office seriously and actually enforced the laws and didn't exercise powers that exceed those enumerated in the Constitution, then I suspect that 2000 page bills that nobody read before voting would be a thing of the past.
Why all the words?
IT’S SIMPLE: President dont just execute laws, they sign them into law - or not.
1. GOP CONGRESS + GOP PRESIDENT WILL REPEAL OBAMACARE.
2. OBAMA WILL VETO REPEAL.
So OBVIOUSLY the fate of Obamacare depends on who is in the White House. Obamacare WILL be repealed if republicans are in charge.
Sorry for shouting but you are seriously lost in the weeds and missing the point.