Question about the attack

"Did they use Cobalt/salted bombs or Neutron bombs?"

As far as I can tell, it was just the standard hydrogen bomb. Cobalt bombs like the kind used in On the Beach don't actually exist, and the film doesn't say anything about neutron bombs.

The town where the family lived was far enough from San Francisco (where the husband was killed) not to get any physical blast damage, but not far enough to escape the wind-borne radioactive fallout, which accumulated over the course of a couple of months, until it killed most of the cast.

Surely it wasn't a neutron bomb as a neutron bomb kills without fallout. That's the whole point of it though there is no evidence such a bomb actually exists.

It isn't specified. Watch and accept the message, instead of being hyper-focused on details that don't really matter. If you were that mother and everyone around is slowly dying of radiation sickness, would the specifics of the bomb really matter?