You can seek and involuntary conservatorship. The days of a doctor's letter and off the person goes are gone. Your facts above do not give anthing but conclusions to analyze.
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.