I'm not sure that will help. I have diagnosed him with suffering from Narcissistic Personality Disorder and as such he rarely listens to what anyone else says. Though it may be a counter against his paranoid tendencies
In that case, take out the little ink pipe from a Biro and discard it, then keep the empty pen in your back pocket.
When he next goes to the stationary cupboard follow him in, shut the door behind you and stab him repeatedly in the throat. Leave the pen there for all to see and exit the cupboard in tears, claiming that you found him choking on a pencil eraser and you were trying to save him with an emergency tracheotomy.
In that case, take out the little ink pipe from a Biro and discard it, then keep the empty pen in your back pocket.
When he next goes to the stationary cupboard follow him in, shut the door behind you and stab him repeatedly in the throat. Leave the pen there for all to see and exit the cupboard in tears, claiming that you found him choking on a pencil eraser and you were trying to save him with an emergency tracheotomy.
Even if he lives, he will be a mute.
Now get to it!