Wills and 401k beneficiaries

Dear Len & Rosie,

My aunt passed away. She left a will leaving her estate to my son and my half-brother and I. Her will even spelled out that we were to receive her 401k. My sisters haven't had any contact with my aunt in over 20 years. She made it quite clear to me, and to others that she would not leave them a dime.

The problem is that my aunt had also signed a beneficiary form in 1974 leaving the retirement account to my father, who is deceased. My two sisters and I were named as the alternate beneficiaries. Now my sisters are after the 401k money that they feel is owed to them! The total amount of the 401k is about $270,000.

I do not speak to my sisters unless absolutely necessary, we do not get along. Should I hire a lawyer and fight my sisters? I know my Aunt would be furious over this! When NY Life contacted me about this they called it An Employee Progress Sharing Plan. I did not realize that it was her 401k and I gave NY life the names and addresses of my two sisters. I contacted my sisters as well. I thought is was some small insurance plan for a small amount of money. I was then told that it was her 401k and flipped. The attorney for my aunt's estate requested an interpleader, which was granted. My sisters have retained an attorney. What should I do?