Can you make someone go into drug rehab?

Long story short, my sister is doing drugs, has threatened to kill herself and her two boys(7&8). She finally admitted to doing the drugs, but says she won't go any where to get help. The boys are in such a bad place. They are hurting more than any one else. I live in Indiana and some places my mom and I have called say that you can't make them do it. But why? She is saying she is going to kill herself and the kids. Shouldn't that be all that it takes to make her. So does anyone have any ideas or has been through this and know what I can do to make her get help for her and for her kids. Thanks for all of your help.

: http://alcoholdrugstreatment.info/can-you-make-someone-go-into-drug-rehab