The 25th Amendment does not require the president's cabinet
It is often assumed that the 25th Amendment requires cooperation of presidential cabinet members to determine whether a president is unfit and should be removed.
This is false. In the event a president is mentally or physically incapable of fulfilling his duties, the 25th Amendment provides two options. The first option provides that “a majority of either the principal officers of the executive departments,” i.e., cabinet secretaries, determine whether the president is incapable of governing. The second option does the same by “such other body as Congress may by law provide[.]” (Amendment XXV, Section 4)
Thus, Congress is permitted to bypass the cabinet and take the first step toward removing a dangerously unfit president.
After the congressionally-appointed body finds him unfit, Congress and the vice president are required to give the House Speaker and Senate President “their written declaration that the President is unable to discharge the powers and duties of his office[.]” (Ibid.)
Since the 25th Amendment has never been acted upon, the vice president’s role is not entirely settled. Questions remain. Is the vice president required to stand by the findings of Congress and its appointed body? Or is he allowed to veto Congress, and thereby hold extreme power over the process?
When such uncertainties arise, the wise thing to do is err on the side of preserving our republic.
allows Congress to make that decision.
“or of such other body as Congress may by law provide”
The problem with your suggestion is that first the law must be passed creating the Congressionally appointed body that can bypass the Cabinet. That law would have to survive a certain presidential veto.
While the veto could, in theory be overruled that would take a 2/3s vote of BOTH houses.
By contrast, impeachment requires only a majority vote in the House and 2/3s of the Senate. That makes any effort under 25th Amendment objectively more challenging than impeachment. Quite simply, if you don't have the easier to get votes for impeachment, you don't have the votes to create this Congressional body.
“ The use of the phrase ‘Vice president shall’ would normally place an obligation on the vice president to do whatever Is dictated in the next few words.