In Washington, the bank may lawfully pay funds to the survivor of an account held jointly with rights of survivorship or to the individual named as a pay on death beneficiary in the contract of deposit.
If your brother was designated as either in the Contract of Deposit, the bank is not liable to you for the funds. You might be able to contest this payment to your brother in probate proceedings.
Attorney at Law
Blado Kiger Bolan, Tacoma, Wash.