Account closed without notice

My parents opened an account for my brother and used to put money in it, unfortunately they were unable to put money anymore so they just left the money in the account. When my brother was in matric my parents went to enquire how much is in the account, to his surprise the consultant told him the account has been closed due to lack of activity. My parents assumed that bank charges ate up all the money and left it like that. I was disgusted to hear that the account was closed and no one was notified and the money just disappeared. I went with my brother to FNB President Square in Krugersdorp to find out what happened. I was told that the account was closed and the money was given to government. How do you give away someone's hard earned cash before you give them notice? The way that we get called or sent sms's when we are owing couldn't FNB do the same to give the rightful owner the money or send a cheque to the address they have on the system? I demanded that they pay back the money, now we waiting 48 hours so that it can be sorted. We were told that we NEED to open an account with FNB first before we get the money back. As soon as the money is in we want nothing to do with FNB they can keep their account.