Do you want the code to heal some one or do you want to make it where using battle commands you can heal someone.
If you want it where you can heal someone using battle commands you need this
plugin by Himeworks. And that plugin depends on
this plugin.
Something like this:
View attachment 6674
If that's what you want what you need to do is:
What you do is make a skill, that's a healing skill and then using note tags in class note boxes, make it were everyone has the skill directly in the actor battle commands.
I use it my game to make an actor command where everyone has the ability to heal instantly however they loose a random 4 -10% of XP they can get.