Rich, I think that anything >2 is considered strongly positive, and your mom's fish score seems very close. Here's a link to the PathVysion web site which explains Fish and Her2+, check out the CEP 17 info. Also, post your question on the main board for more input, there are others who are more informed than I am on this subject who will be able to advise you. Access the main board by clicking on Message Boards above, then go to Her2 Group.
http://www.pathvysion.com/Home_2.asp?bhcp=1