Interesting story. First, it is impossible for a liver to be as small as a 50 cent piece, even for a significantly shrunk liver. The human liver weighs several kilograms. So it would still be large even if it has shrunk in size. Second, if the friend of your mom stopped drinking, the cause of liver injury would be gone and she would probably regain a normal liver function. However, this does not necessarily mean that the liver in this case regrows. Finally, I am trying to answer the question of this thread "Can a liver regrow itself if a person has cirrhosis really bad". The answer is no. For terminal liver cirrhosis, the only treatment is liver transplant. However, in other situations, for example, when you have been a healthy person and then you were found to have a liver tumor, and the surgeon cut off a half (or 3/4) of your liver to remove the tumor, your liver would likely regrow to the size prior to the surgery.