Mother being sued, what can we do?

My mother's being sued by my cousin for roughly $83,000. Three years ago, my aunt (my cousin's mother) had numerous strokes over the course of a few months, and needed someone to stay with her to care for her. My mother, despite her doctors telling her that she was unable to due to her own health, stayed with her almost everyday for two years providing all of her day to day care. In October of 2007, it was decided that she needed to be placed in a nursing home. My mother and cousin were each named her power of attorney. Though my cousin was named power of attorney as well, he did not participate in any meetings with lawyers, the sale of the house, or the sale of her belongings, nor did he provide help in her care. The house was sold for $69,000 with the broker recieving $5,000. The lawyer representing my aunt told my mother to pay off all of my aunt's bills with the money from the sale, which she did. My mother did ask my aunt if she could borrow $5,000, which she allowed her to do. She signed a written consent, however, it was not notarized. But she did repay the money. Now, my cousin is suing my mother, saying that of the money from the sale of the house, that my mother spent around $33,000 on things that were not for my aunt. He's asking for the $33,000 in compensation, as well as $50,000 in punitive damages. Can he do that? What can my mother do to defend herself? Can we counter-sue for abandonment on his part? We have a month to respond to his lawyers one way or the other, so any real help/advice would be appreciated. Sorry for it being so long. Thank you.