What Causes Foggy Brain Symptoms?

My father almost died with a CHF attack... he was in the hospital and is not in rehab for a few weeks... he also has some liver disease but his enzymes are not up... no one knows why he has this foggy brain symptom or why his feet feel numb all the time... he has no signs of diabetes. He was born with bronchiecticy (spelling?) of one side of his lungs... Any ideas on these symptoms... also he was sitting in a chair eating his supper and said he had to get into bed because he felt like he was going to pass out. Any ideas? Would appreciate any ideas you might have on these symptoms... Lori