The relevant rules seem to be: "Choose a 3rd-level or lower spell that does not attack a creature or deal damage." "Usually, a spell-like ability works just like the spell of that name." and "Touch Spells in Combat: ... You can automatically touch one friend or use the spell on yourself, but to touch an opponent, you must succeed on an attack roll."
So, if it works on anyone it seems like it should work on the foe and their friends. It shouldn't work on the foe's opponents or creatures damaged by positive energy.
The only question is whether "Cure Serious Wounds" counts as a spell that attack's a creature or deals damage since it does so against opponents and undead. I'd probably rule that it works as healing only and only when no attack roll is needed.