It will be several years at least. But you're correct, he will live in a psych hospital for a few years where they will put him on clozaril or zyprexa. He will eventually be shipped off to a group home where he will refuse his meds for a few days, then abscond, and be on the streets smoking/drinking everything he can find until he is either caught (HIGHLY UNLIKELY) or until he offends again and the police bring him in for a NEW violent crime. This will go on for decades until the offender is physically incapable of leaving his bed. Ask me how I know lol.