(((((Ivy))))) I am so sorry to hear about this horrible situation that you write of. I do not believe that your Son can be held accountable for his actions. However the hospital technician and other personel there should be held accountable for having unhooked all of his wires etc. And for not monitoring a suicidal patient more carefully. THEY are accountable.
I believe that a good lawyer can get the case against your son dropped. Because of his mental condition, and the neglegence of the hospital. AND sue the hospital for negligence.
Ivy, This was not your fault. I think you would know this to say to another mom who was in the exact same circumstances. Hindsight is always 20/20. But it can be extremely judgemental. Often people who are suicidal are experts at hiding it from everyone. Please give yourself the words you would give to someone whose son was in the same situation. I am thinking of you both. Truely.