The tire has got a nasty scratch and the inner tube was bursting through... which does not help with preventing leaks. She ordered a new tire (white!) but it won't arrive for a week.
So I googled the problem "booting the tire" and found this solution!
I have a spare dollar or two that I haven't exchanged for euros.
How to Boot a Tire for Bike Maintenance -- powered by ehow
So last night, my friend flipped her bicycle in front of the house and we went to work on the tire at about 17:15.
By 17:18, a man had walked by, offered advice and when we expressed a polite curiosity about his opinion, he took the tools and did all the work for us. He was skeptical and amused about the dollar bill solution but agreed to do it. His daughter watched him fix the tube and tire for us and eventually his wife came by and they all left in a car.