GUI Over AI characters

Is it possible to have a GUI (in the form of a meter) be on top of an AI character's head and follow the AI where ever it goes? Oh and can the GUI decrease should the AI be damaged by the player?

Is it possible to have a GUI (in the form of a meter) be on top of an AI character's head and follow the AI where ever it goes?

Yes.

Oh and can the GUI decrease should the AI be damaged by the player?

Yes, it can.