Well If you want him to use it continuously use this-
;Artificial Intelligence Script
;Header
desc = Health Station
;Triggers
:state=0,plrdistwithin=100,plrusingaction=1:state=1,plraddhealth=30,plrsound=audiobank\items\healthup.wav
:state=1,plrusingaction=0:state=0
;End of Script
And this code if you want it to be only used once-
;Artificial Intelligence Script
;Header
desc = Health Station
;Triggers
:state=0,plrdistwithin=100,plrusingaction=1:state=1,plraddhealth=30,plrsound=audiobank\items\healthup.wav
:state=1,plrusingaction=0
;End of Script