You will have to contact the trustee of the 401k.
They will have a process in place for situations like this.
you don't cash it out - you should get it rolled over into an IRA in your name
You contact the company, file a claim, give them a copy of the death certificate and if you are the named beneficiary they will pay you.
go to bank and ask them lol and make sure you sent some to me lol
speak with your estate attorney. the one handling the probate, as to the proper procedure.
