You can only "take medical control" if your mother is found by a court, based on medical evidence (e.g. medical tests; testimony by doctors who have treated her) to be mentally imcompetent and unable to manage her own affairs, and you are appointed as her legal guardian. This can be a difficult thing to do, since the law does not like taking away peoples' control over their own lives and requires strong evidence of incompetence: e.g. of an inability to appreciate her own condition or to understand what needs to be done, or being the victim of uncontrollable impulses. Just making poor or unwise choices is not enough. If you wish to explore this option, consult with an attorney doing elder law or who represents the disabled and their families: such a lawyer should understand how to apply for a guardianship.