Herbert is a Rat Swarm with Psychic levels.
As such, he is able to cast magic and has the Int score on the level of a wizard.
A swarm is immune to any spell or effect that targets a specific number of creatures (including single-target spells such as disintegrate), with the exception of mind-affecting effects (charms, compulsions, morale effects, patterns, and phantasms) if the swarm has an Intelligence score and a hive mind.
This tells me that while Herbert is immune to spells like Disintegrate or Magic Missile, it is also Immune to Haste or Cure Wounds spells.
Now, the Question!
I do notice that I have spells with a target of "You".
Is there any ruling that would tell me whether such a spell "targets a specific number of creatures" and therefore would function on a Swarm? Not looking for interpretations or guesses, just hard rules!
(This question only applies to non-mental spells, as a Swarm with a hive mind has no immunity to mind-affecting spells.)