Looking at your friend's situation, if she is unable to check her presto card balance online at prestocard.ca, because her computer is not working or she doesn't have phone data plan, there are other ways she can check her presto card balance:-
1. If she happen to pass by any of the Toronto Subway stations, there are green coloured presto card self serve reload machine where she can insert her presto card and check her card balance.
2. If she is no where near a TTC subway stations, she can call the number 18773786123 and choose "Self Serve Menu Options" when she hears a voice prompt.
Press "1" for English choice.
Then Press "2" to choose existing prestocard user options.
Then Press "2" to access presto card details using your last 11 digits of your presto card number.
After that, you will be able to hear and check the balance of your presto card.