How Can Diarrhea, Vomiting With Nausea And Body Soreness Be Treated?

Hi, my mom had diarrohae and vomitting for the past 5 weeks. She has also stopped smoking because she felt so ill. She has seen doctors and they say there is nothing clinically wrong with her. She is also diabetic. She refuses to take her pills, has no appetite as she feels nauseaus all the time. She is vomitting clear phlegm, she refuses to take her medication, she says her body is sore, her head is sore and she has also given up smoking for the past 3 weeks. Please help me. Could there be something wrong with my mom or could she be in a depressed state.