It may be a range issue. Currently, in Issue Six, henchmen prefer certain attacks at certain ranges. At a far distance there may only be one or two attacks they'll use. At mid, they'll use a few more. At near they'll use something different. And at melee they'll only use melee attacks.
This is partly fixed in Issue Seven where even in melee a hench will use all the powers they have.
Trick is to learn the best range for your henches and move them there (using Follow or Goto) and then let them attack.
sorry to take so long to reply but been ill.
Char is a buff power, not an attack but still can't make him trigger it.
Me and my other henchmen even tried a group hug to get him to use it 
Too many 50's to list here's a few you may know.
Slazenger, Area51, Area53, Area54, Erruption, Mind Plague, Thresher, Sheath, Broadside, Debt
Uh....Char is a Mag 3 Hold with Heat based DOT, Controller Tier 2. (And glad to hear you got better 
)
As detailed here
Yup, char is the fire control hold.
lol what a plonker.
Just had a word with the person i teamed with the day i thought my henchie buffed me, seems it was Forge not Char.
That would explain why my Oni not so useless after all.
What makes it worse is i have an alt with both of these powers as well
Too many 50's to list here's a few you may know.
Slazenger, Area51, Area53, Area54, Erruption, Mind Plague, Thresher, Sheath, Broadside, Debt
How guys just a quick question....
ONI anyone know how to make him use char all the time, mine just seems intent on causing pain with Rain of Fire.
Iv'e had him about 2 months now and in that time he has used Char once, am i missing something is there something special involved to get him to use this power?
Too many 50's to list here's a few you may know.
Slazenger, Area51, Area53, Area54, Erruption, Mind Plague, Thresher, Sheath, Broadside, Debt