Well, we know that You can automatically touch one friend or use the spell on yourself, but to touch an opponent, you must succeed on an attack roll.
We also know that Concealment gives the subject of a successful attack a 20% chance that the attacker missed because of the concealment.
So given this, we know that if your friend has concealment, any successful attack you make against him has a 20% miss chance.
The question is - is an automatic touch, requiring no attack roll, delivering a beneficial spell to a willing ally, considered a 'successful attack', or not an attack at all?
If it's not an attack, concealment provides no miss chance. If it's an attack, then despite requiring no attack roll, the automatically-successful attack might still miss due to concealment.
-Hyp.