Did YOU replace the tires or did a shop do it?
Yes, I know that replacing a tube is easy but many people forget to check to make sure the rim strip is intact, and to check inside the tire by FEELING for any protrusions (don't just look), to make sure the valve is straight, and to talc the tube so it moves inside the tire. A bike shop does all this. My first line of action after thorough checking is to replace the rim strip with one made of fabric, available under the brand name Velo.
Another possibility is the method by which the new tube is installed- tools, especially screwdrivers, should not be used to pry the tire on or off. Using a bit of muscle all but the most stubborn tires can be removed and installed by hand.
I suggest that you walk along the route normally ridden by your daughter and see if there are any places with sharp stones, thorn bushes, or other things that might compromise the tire and then the tube.
Finally, never repair a tube more than twice. The patch doesn't allow the tube to expand properly which stretches it abnormally and places stress on it.
