Well, THAT is when strategy comes into play: If the monster is immune to "stop" you need to give Fran a different gambit

I have my 12 gambits like thus:
1-4 cure ailments with items (or revive and first aid on one in my party)
5-8 use magic (bubble, drain, gravity, etc..)
9-12 use techniques (for when you are down to 0 MP) like 1,000 needles, Addle, etc...

I change the magic gambits often because you can't use drain with undead and gravity, stop, et.. there is always a monster that is immune to it. The rest stays fairly constant, unless I'm running low on potions or phoenix down, then I go with revive and raise