bypass side effect,memory loss?

My mother,a diabetic who is now 65 had triple bypass surgery in 2001.
Before my mother had the surgery she was known as the sweetest person you would ever meet.
After the surgery me and my siblings noticed an extreme change in her personality.
Now my mother losses things on a daily basis. When you speak to her it is hard to have a normal conversation because its like she has a one track mind. I feel that its to hard for her to comprehend what im saying and still remember what she was trying to get out. so its usually just her saying what she has to and not listening to what the other person is saying. this is a huge problem because most people think its her being rude and this usually leads to arguments with almost everyone she comes in contact with. I know that she is not doing this on purpose leading me to believe that it has to do with the bypass because that is around the time that all this started, is this possible? could something have happened to her brain from the surgery that would make her so forgetful and make it so hard for her to carry out normal conversations.

[ed34]

Has she had a head scan to see if she suffered a stroke?