Maybe if you could pay for something in real life like a meal out or buy her something she wants and let her see bitcion being used then that may help as they will see a real world use for it.
I agree with you. And he could also show her some internet sites that lets pay in bitcoins, for example clothes store, and tell her how it is easy to pay with them, i am sure she will like it
I don't think it will work as girls are not more interested in earning money, they know only how to spend them and they want everything ready on table so I don't they will make any efforts in earning it.