He needs intervention. That should be your primary concern. If what he did is against the law and the T has to report it, so be it. It is a well known fact that cruelty and torture of animals can be a precursor or entry crime to treating humans in a similar manner. Sorry to be so blunt, but this is important. The safety of someone may be at stake.
“Life’s journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy ____…! What a ride!’” ~Hunter S. Thompson