It is not my normal policy to gravedig, but I wanted to address this point.
Forcing military personnel to go on a suicide mission by threatening to imprison or kill their relatives would undoubtedly work with some individuals, but this method also runs the risk of backfiring spectacularly. Anybody coerced by such a method is going to be extremely resentful (to put it mildly) and some individuals placed into this position might respond by simply pretending to agree to take the atomic weapon into enemy territory on a suicide mission; upon arrival, they might well be brave enough or resentful enough to turn the weapon over to the other side and to urge them to use it to destroy the capital city and the leaders of the dictatorship which has threatened them and their families. Some might be idealistic enough to sacrifice their family members to accomplish this; some might not believe their government’s promises that their relatives will not be harmed if they cooperate (governments who rule at gunpoint don’t score very highly on the credibility and trust scales); and some might conclude that the best chance their families have of surviving is to eliminate the dictatorship before the dictatorship can eliminate them. Personally, an atomic weapon is something I’d only place in the hands of people in whom I have absolute trust, not in the hands of people I’ve threatened and antagonized.
All of this is certainly true. However, there is a way around the problem.
Naval mine technology of the era could easily be adapted to utilize a nuclear weapon, with a timed detonator, and towed to the target by a fully manned (and fully loyal) submarine crew.
It would take some specialized training for deployment in shallow water. It would also require some technological modifications, as the mine would need to surface just prior to detonation. These challenges are easily manageable by any navy of the war.
So forget all about those suicide missions.