hi
thanks for posting in HCM
I have understand your concern
most probable reason for his problem is upper GI bleed only , because dark stool indicates only upper GI bleed and
colonoscopy also Normal.
mostly naprosen induced ulcer bleed or some other cause.
I can suggest him to get done upper GI endoscopy , if it is already done , he can undergo
capsule endoscopy which can find out bleeding spot where colonoscopy and endoscopy can't reach.
one more scan is there, that is
RBC scintigraphy or bleeders scan , all these are costly
meanwhile if his HB is less than 8 gms , he needs
blood transfusion.
somatostatin infusion also helps in controlling bleeding
hope this helps you
any further questions please let me know
thanks