I doubt that the military will let him launch anything, except on warning of imminent attack. They kept the football from Nixon near the end and this tyro is at least 10X worse than Nixon ever was.
Consider whether anyone would have anticipated the Cuban missile crisis hours before news of the missiles in Cuba was leaked? By way of parallel, we know that Kennedy at the time was under the influence of drugs but seems to have performed well. I have never been satisfied that we have the accurate history of these events in which Kennedy and his brother were portrayed as the sole exponents of reason beating back Curtis LeMay and the "knuckledraggers". But, based on the facts as we now know them, we must concede Kennedy performed well.
However, it is not a happy prospect to have a commander-in-chief whose condition-whether drug addicted, narcissistic, or Marxist, or any combination of the three-is potentially unstable.