Hello As you mentioned that your mother is having typhoid fever and not responding to treatment . You didn t mention the drugs , used for treatment so very difficult to say some thing about drugs. In resistant type of cases a DEXAMETHASONE treatment should be considered .In Jakarta in chloramphenicol-treated patients, treatment with dexamethasone ( a single doseof 3 mg/body followed by 8 doses of 1 mg/ kg body weight given every 6 hour). This treatment was only for very severe cases and provide instant relief. But in your mother case fever may be due to . 1 Tuberculosis , so get in X RAY chest as well sputum for A F B , blood for c b c& es r. 2 Jaundice may be the another reason as I have seen oin my so many patients that prolong fever is due to jaundice so get all test for HBASG A B C D E. 3 Another reason of this prolonged fever may be renal failure . As there was U TI and this may be the reason . Diagnosis can be confirmed by urine culture and sensitivity test . Also get in M R I of both kidney. However there are so many other reasons of such fever . But in my opinion consult another physician and get his opinion ( 2nd ). Good luck.