Welcome to HCM,
After going through your history ,if some one suffers Typhoid usually it is cured in 2 weeks time and it is more important to diagnose clinically and take complete treatment,but once it is treated widal test
may remain positive for some time then titre starts falling to reach herd immunity level.
If she falls sick again and again as it is water born disease take care of potable water and food items which takes.
It is also possible to have false positive report of positive widal in various other disease like malaria
She must be investigated properly not to miss any other diagnosis.
Now a days widal test has limited value and for Typhoid if Blood culture
is available must be used for diagnosis along with clinical features and findings.
You should get her X ray chest and Ultra sonography
to exclude other possibilities, please discuss with your treating doctor.