Number one thing is keep your child & yourself safe...

I don't know if anyone might be able to record or video him in the violent state of mind?

Then play it back to him later, and also perhaps show it to his drs so they know something is wrong...
Maybe the part of the brain that affects his emotions, or lack of control, was the part that was involved in the procedure.

And perhaps something is not really 100% fixed, or some other area might have been damaged?? Might need an independent opinion..from someone other than the drs that did the procedure.