Aunt trying to "steal" Dad away

Hi - My Dad, who is 76 years old, just lost his job after working reliably nonstop for 55 years in one field, due to the "sequester." My aunt, who hides it well but is *very* selfish, is already maneuvering to try to arrange events so that he will move 3,000 miles away to be closer to her. (She married her second husband for his money so it's not like she has any financial problems - they're literally multi-millionaires.) Every time I indicate that we need him here and that this is his home, she essentially disregards it and pretends she literally doesn't understand what's being said. How do I get her to back the hell off without causing trouble or stirring the pot?

your dad must be also encouraging her,have a talk with your dad about this