Memory Loss and Confusion Related to Gastrointestinal Conditions?

Hi,

My mother is 70 years old and had multiple surgeries related to diverticulitis starting in 2006.  There was a total of 4 operations, with the last one completed in 2008.  The original surgery, back in February 2006 was because the lower colon was perforated and that portion was removed, resulting in her having a colostomy.  The second surgery happened about 5 months later to reconnect the colon.  For about 1 year after the second surgery, bowel movement showed traces of blood and she went to another doctor to discover that the site of reconnection had become a smaller opening where matterials passing through the reconnected area possibly caused the bleeding.  So, they again cut that section in the rectum resulting in her having an ileostomy for a few months.  Finally, in November, 2008, they reconnected all portions and the bleeding did stop.

She has been more forgetful and at times, confused/disoriented ever since she had the surgeries.  

1) Is there any relationship to the drugs they used for enesthesia and memory loss or declined mental capabilities?
2) Is there any relationship between the intestinal system having been injured due to multiple surgeries and declined mental capabilities?

Please inform and point out any resources/reading I should check out to learn more/get the answers.

Thank you.