I think it would be wise to be deterred by an old man walking around at the G7. Putin (and moat Americans) know nothing about the person who will let Crooked Joe know when it’s time to hit the button. It’s starting to look like crooked Joe isn’t really in charge of the arsenal.
I would guess that one of the "Senior Presidential Advisors" on the Administration staff has the cue cards that would be used to activate the nuclear attack orders. I believe it is unlikely that Biden is even capable of using them.