Suffering With Paranoid Schizophrenia, Has Fluctuating Behavior. Advisable Treatment?

My mother 11 years ago was subject to a nervous breakdown, which later going untreated, developed into what the dr said was paranoid schizophrenia ,she fluctuates from normal behaviour to irrational behaviour(non violent) for instance now she has taken to eating only broth until december, this has been going on for months now, (as she states people are attacking her internally)she needs a mental assessment but refuses to go to a dr .I do not know what to do and I do not mind paying for an assesment, but how and how much