State laws regarding conservatorship and mental health

 Hi. I'm a licensed clinician in the state of California, so I'm not at all familiar with Michigan laws. I can say that some states refer to conservatorship as "guardianship" or "trustee." When a family member is seeking to keep another family member in "treatment," usually the courts become involved to provide that appointing privilege to a capable family member. The circumstances must be severe enough to warrant this, as the courts have mental health appointed workers who psychiatrically evaluate a person who is allegedly incapable of making legal, financial and medical decisions for themselves. This condition is usually referred to as gravely disabled or a person may suffer from a sever developmental disability in which they cannot take care of themselves. Chemical dependency issues, if that is what you are referring to  "rehabilitation center" is not the same. A person with a substance problem may have to experience legal problems related to their chemical dependency, severe enough where the courts order that person to attend and complete rehab as part of a sentence, but not always. As far as I know, I'm not aware of family members obtaining legal rights to mandate a person to rehab treatment. I would highly recommend getting legal advice within your state of interest. Best of luck to you.