Is there hope for memory loss??

On Thanksgiving Day 2005, my father suffered a massive heart attack.  The stent procedure was a success, but the outlook was grim.  He pulled through.....then 2 days later he had a "code 99" while in ICU and had no pulse for 14--15 minutes.  They were able to resucitate him, but he lost his short-term memory due to oxygen deprivation to the brain.  He also seems to be missing certain pieces of long-term memory as well.  His outcome/recovery was better than expected (they thought he would have severe brain damage and/or continue to be on life support).  We are extremely grateful that he made it!  However, the memory loss is very challenging for my mother, and it's very sad as well; he knows his daughters but not all of his grandchildren (or anyone who came into the picture in the past few years).  He seems to be able to retain small bits of certain information that is newly learned, but this is rare.  It has been 1 year and 8 months.  Is there any hope for his memory to improve?  Does the brain repair itself at all?  What can we do??  Any info or advice would be much appreciated.