1) I am not sure about FULL recovery but I think a significant improvement is very possible. 4 years later I still am not 100% but pretty close!
2) Less than a year after complete removal of alcohol and staying with a vitamin regime
3) Centrum Silver has been my choice, along with benfotiamine (sp?) and r-lipoic acid at the start.
4) No, I am learning how to play guitar right now and the fingers work perfect. Tell him to stay with it, the tingling and numbness will go away in the hands if he stays off the booze and lets the nerves heal slowly.

All the best to him (and you) as you wade through the depths of this disease. I do, however, recommend that he get involved in some meetings whether it be AA or CR. They are tough to manage at first, but they can be a big help knowing there are others in the same boat.