Hi.
Thanks for your query.
Noted the history about your husband and understood your concerns.
2 weeks is a long time to suffer from viral infection that caused
stomach flu.
It is possible that there may be a bacterial infection too.
This can be detected by the following ways:
Get a blood tests done for CBC, typhoid, liver and
thyroid functions and also culture and sensitivity.
Get the stool tests also done.
X-ray and
ultrasonography of the whole abdomen helps further.
Since there is tremendous
fatigue, serum electrolytes also should be done.
If a Bacterial infection is found during the course of investigations, a course of an antibiotic,
metronidazole and probiotics should help him the best.
Electrolyte solution, plenty of oral fluids including fruit juices and multivitamins may help to get a faster recovery from the infection and fatigue.