NB. The Prof has been in touch with Mum and he's obviously booked into Vienna as well with his wife (from Canada) - airline tickets, babysitters, time off work etc - thinking Yose was not a scammer.
He has invited Mum our for dinner with his wife in Vienna. It appears Mum has booked into a Hotel in Vienna for a few weeks and will take to tours to Prague etc instead.
You can be a genius in one field, but time and time again, many who are far removed from the commercial world have little understanding how some scam artists operate.