It's really easy to get evidence of these things. People can log onto Centrelink and download a statement directly (I believe).
You can also get their rent paid directly by Centrelink, the property managers should be able to sort this out.
I suppose it depends in the context of their overall living expenses. After paying the rent, will she have enough money to pay the other bills & send her daughter to school?
Are there reliable alternative sources of income? Centrelink, husband, etc?