Guardianship to hande expired Nephew estate, and beneficiary who expired 2007

My Nephew worked at Walmart in Richmond, va and expired 10/30/2018. I contacted Prudential who handles Walmart 401k and life insurance policy. I am not getting anyplace.
My Nephew was mentally challenged and Richmond Residential and Supported employment of Virginia did not release his funds. I had to pay to bury him and have receipt. I need to settle his estate, but also want to get guardianship for his life insurance policy and 401K plan.