Do I need a probate lawyer if keeper of retirement fund only requires an Estate to be set up?

My Aunt died in November 2009 and named my father as one of her beneficiaries on her ALCOA retirement. My father died in December 2009 so my mother has been working with an estate attorney since and is now being told by said lawyer that she needs a probate attorney. According to ALCOA, they only require the following to release the funds: A small estate set up in my father's name, a Letter of Appointment filed with the court naming the executor of his estate, and EIN, copies of the executor's driver's license and social security card. This has been going on for a year and a half now and my mother is at her wit's end. Help!