Can You Force an Adult in Indiana Legally to Go Into Rehab or Go to Jail?

I’m fearful of losing my 31-year-old boyfriend to a very serious Heroin addiction. I think he deep down inside wants to get better. He has done very little though to find help as he gets frustrated because he has no money or insurance for a rehab facility. He is on death’s door. I’ve seriously considered finding a way to have him arrested but I KNOW that jail will only succeed into keeping clean while he’s there and the second he get out, he’ll use again. He’s done a couple of stints in jail for a few weeks and it did no good. He really needs at least a 3 month drug rehab inpatient treatment facility followed by going to a halfway house or a sober living facility. I don’t want to give up on him. PLEASE HELP! Any links or personal experience stories is greatly appreciated. I’d really like to hear from a lawyer or law student or even a police officer that has dealt with individuals like these. He still has so much to offer this world. When I met him 9 years ago, he was clean and totally different. He was hard-working, very likeable, honest, and strong. He is none of these things now. PLEASE PLEASE PLEASE HELP! I do NOT want to have to go to my boyfriend’s own funeral.