I stand corrected. He did note the existence of the impeachment process.
Two paragraphs earlier, he points out that criminal investigations against the president are unreliable because of partisan meddling or distrusted because of accusations of partisan meddling. Yet he wants to rely on an unabashedly partisan process for removal that would not, under his system, have the benefit of any type of investigative process.
So, logically, it follows he’s either advocating that the president should he removed based on accusations without investigation. That would certainly be ironic. Or he’s arguing that the only method for stopping a corrupt president is to get 218 representatives and 67 senators to put aside their partisan differences and agree without investigating, that the president should be removed from office.
He lived it. He knows that impeachment is an empty threat for any president that has any type of sizable minority in the senate.
It is an objectively expansive view of executive power and one that is rightly criticized by legal scholars from both points of view and just about anybody else capable of more than a superficial analysis of what he’s saying. It’s criticized not only for being over broad but because it effectively creates complete immunity in any situation where the executive branch and a sizable minority of the legislative branche are philosophically aligned.