I have committed my AH 3 different times.
I realize each state is different, so check with yours, but...
In Iowa you need to have 2 people who have recent knowledge that he is a danger to himself or others.
There are papers that need to be filed at the court house and then the police/sheriffs pick him up and take him to a hospital for detox - where the dr. makes a recommendation for treatment.
Of course even that doesn't always work. Case in point my AH.
You can't change someone who doesn't want to change. All you can change is you.