An insane person is never found guilty of anything. Innocent by reason of insanity. They go to a mental hospital not a jail. I don't know if any degree of insanity can be cured. It's like being pregnant. You either are or you aren't.
Having an insane person prosecuted executed electrocuted would be a tragedy. Having them "put away" for life so they cannot harm others or themselves is what they usually do. Now of course I guess folks can fake crazy and maybe some have to escape imprisonment or execution. Remember MASH and Klinger always dressing as a dame so he could use a Section 8 to get out of the army? Of course they ignored him. I expect it can be pulled off and has.
However why would don pretend to be insane? He simply is and therefore he is not to blame for what he does since he doesn't know any better and cannot control himself. We should aim for his enablers/facilitators. They are doing him GREAT harm by their protecting facilitating. To what end? Well it won't end well for anyone and they are the ones to blame entirely for what is going on, what has gone and what will go on.