Hello
I want to tell you that
typhoid fever is an intestinal fever . S. typhi 1:120 is positive but it will come down after 3-6 months of treatment stoppage.
Your grand mother was prescribed right medication ( cefixime as well as ceftriazone ).
If still she has fever then it is a cause of concern and consult a physician for 2nd opinion.
As you mentioned that once drug stopped fever recurs , so such type of fever may be due to these reasons , these include:
1
Jaundice , as this is a common cause of such prolong fever . Diagnosis can be confirmed by hbasg for A B C E .
2
Tuberculosis , for prolong fever , this is also a most common cause of fever. Diagnosis can be confirmed by Chest X ray , as well as blood for cbc , es r.
3
Urinary tract infection , diagnosis can be confirmed by urine examination.
In old age there are so many other causes of such fever like , chronic infection , anemia ,
resistant typhoid , so consult another physician and get his opinion ( 2nd ) .
Good luck.