https://www.federalregister.gov/presidential-documents/other-presidential-documents/joe-biden/2024
https://www.justice.gov/pardon
The effective precedent for the current situation seems to be the Woodrow Wilson stroke of October 2, 1919.
In that case, the accepted history is that Vice President Marshall declined to assert that Wilson was unable to discharge his presidential duties (and 25A had not yet been written and ratified). Wilson did not appear in public after September 25.
After Wilson’s October 2 stroke, Wilson only saw his secretary (Joe Tumulty), his physician (Cary Grayson), and his wife (Edith).
The public became aware that Wilson had suffered a stroke in February 1920.
Some historians assert that the presidency was controlled by Edith Wilson, from the time of President Wilson’s 1919 stroke until Warren Harding was sworn in on March 4, 1921.