hello
welcome to hcm
i can very well understand your concern for your mother,well there are many possible causes for presence of blood in the stools since long..here is the list of possible causes--
(1) haemorrhoids i.e bleeding piles
(2) anal fissure
(3) fistula in ano
(4) intestinal hookworm infestation
(5)
inflammatory bowel disease specially crohn's disease and ulcerative colitis
(6)
diverticular disease of the large intestine specially of the colon
(7) ischemic colitis
(8) pseudomembranous colitis
(9) intestinal varices
(10) portal hypertension
(11) gastric ulcers
(12) intestinal polyps
(13) arterio-venous malformation in the intestines
(14) cancer of the colon and rectum
(15) taking pain killer medicines like aspirin/
ibuprofen for too long
your mother is getting weak and thin due to anemia caused by
chronic blood loss..i would advice you not to waste any more time and urgently visit a surgeon or gastroentrologist who would perform a physical and local examination and will get some tests done along with endoscopy/
colonoscopy if required to make a precise diagnosis i.e to find the underlying cause for chronic blood loss in stools and will guide you about the most appropriate treatment options for curing the underlying disease
i hope you shall find this information to be helpfull
take care
hcm..