Based on what history you have briefly provided,
It is best to have a physical examination of his abdomen to rule out any tenderness or possibility of organ involvement.
A few basic things that I can suggest include :
1. Adequate hydration all through the day
2. Dietary modifications which avoids lactose, street food and high fatty foods. Try bland food such as curd rice , toast etc)
3. Probiotics can also help restore the gut flora
4. If you are living in an endemic area of parasites such as Giardia / Amoebiasis then an emperic dose of anti parasite would be ideal
5. Antibiotics can only be given after results of stool samples
Next Steps
Ideally it is best to have some tests done which include
1. Stool examination : to check for any parasites or cysts
2. CBC, ESR/
CRP : which are signs of inflammation / infection
3.
Thyroid function test: only if not tested in a very long time as hyperthyroidism can cause loose stools
4. If all the above show normal results and your husbands condition worsens or remains the same and causes him distress it would be best to take imagining modalities into consideration such as colposcopy
Health Tips
Please do not take antibiotics without stool or blood sample results as it can cause further loose stools