The pain in the upper abdomen can be due to basal pneumonitis
.Reports suggest persistent infection.
Please continue with Oral antibiotic like Clarithromycin
Another possibility is Acid peptic disease
.please give PPI like Rabeprazole
Get an X ray chest PA view,Ultrasound abdomen and upper GI endoscopy.
If you come back with the reports,i will clarify further.
Wish him good health