How does Art respond to his father when Vladek calls to ask for help with fixing the drainpipe?

One of the primary themes in Maus is that of guilt, which manifests itself a number of ways, such as in Art's feelings that he does not treat his father as well as he should. Art clearly is not close with his father and does not wish to help him. Still his wife urges him to go and there is his lingering guilt over his relationship or lack of relationship with his father.