When you're stunned it wears off rather quickly, often just a round, so generally the problem of "curing" stunning is not much of an issue.
But a Mind Blast lasts for 3d4 rounds, and Power Word Stun potentiall even more.
I don't think there's any "official" way of helping another recover from being stunned, but I'd allow Remove Paralysis to do the job, citing the "from paralysis or from related magic".
But others could (and will, certainly) judge otherwise.