It would need to check that:
- He's my current combat ally (No idea if this is even possible)
- I'm in an area where I can even cast his Combat Ally Ability.
- It's not currently on cooldown (Thought this would be easy but it appears Combat ally abilities don't respond to the usual "Spell ready" or "Action usable"?)
- I don't already have the buff (easy)
Cheers.