Can Sue for Pay-on-Death Monies?

My father died Oct 2005. I am one of 5 siblings. My father had a money market account with $205,000.00 in it. It was POD (stands for “pay on death”) to me. I went to the bank with his death certificate and claimed the money.  My brother who is executor to the will is now threatening to sue me for the money. He says it belongs to the family and not just to me. Doesn’t POD mean Pay on Death? Isn’t the money legally mine? Can he really sue me for it? He thinks it is very unfair that I receive all that money. What should I do?
In most states designating an account POD is an instructionas the depositor telling the bank “at my death the balance in the account belongs to (name of beneficiary).”  The balance in the account does not go through probate or become part of the deceased’s estate.  Your brother may be able to sue you but unless he can show some sort fraud or other misconduct the money should be yours.  If he does file suit against you, contact an attorney immediately.  Do not try to handle this without an attorney.