I feel terrible for your friend I know that it must be awful for her to deal with as I have 3 cats myself and would be devastated if I had done that to one of them........I have nothing to offer other than the simple fact that it was an accident....she meant no harm when she left her house......it just happened.....I think the idea of therapy is a good one because of the guilt that she probably feels.... I hope it all works out for the both you.