This is false. The president can change interpretations of law (this is how E.O. 13233 was couched), but cannot pass a new law on his own. This is in Articles I and II of the Constitution.

In time of war or crisis, people will allow generous interpretations of the President's role to interpret the law, but time catches up.

Obviously Health Care (i.e., ACA) caused huge debate and negotiation with Congress.

The Iraq War resolution (the 2002 one) was a different situation in which Congress passed a wishy-washy resolution that was, in typical fashion, over-extended by the Bush administration. But Congress went along.

The practical distinction may vanish when the other branches do not effectively check the executive when it exceeds its Constitutional power, but that's not inherent in the President heading the Executive branch -- the same is equally true of excesses in other branches, though the unitary nature of the executive provides less of an intra-branch check on abuses by the President than exists for any actor in the legislative or judicial branches (though collective excesses, such as -- as a purely hypothetical example -- the Supreme Court intruding into Congress' Constitutional role in judging the propriety of Presidential electoral votes including the process by which they are assigned -- can still occur and be problematic if left unchecked by the other branches.)