How long is the recruitment process of banks in Nigeria.

So my sister had a phone interview with one of our banks here in Nigeria and after the talk they told her they would get back to her.

This was last month so its been about a month now and still no word from them on the outcome or a next step.

So how long do you think she should keep hoping to hear back from them before considering the fact that they may not call her back for a job ever.