Gee, I thought I was reading an old post of mine. In Australia, you can not force rehab but if you think he is in danger of hurting or killing himself you can call Family Mental Health Services here (must be something similar there) and they will actually meet you at the house and assess them. If they think they are suicidal or in such bad shape as to hurt themselves or their environment they will take them to hospital for further tests and assessment. Here, they wont let them leave the hospital if they think they need help and they will admit them to an appropriate service they need.
Only advise and this was our last alternative some 12 months ago.