Q: New timing belt broke?

Timing belts are rubber based products. Rubber deteriorates with age and that deterioration can be accelerated by storage conditions. I have seen belts vended that are 6 years old or older, which is well past a reasonable interval. Consequently, if you really want to do a proper forensic investigation, I would not assume, at the outset, that it was a "new" timing belt. However, if and once the belt is confirmed new, a failure of this type could be due to a manufacturer defect or a circumstance where one of the rolling elements, such as a pulley, tensioner, or belt driven device such as a water pump, seized or is seizing. In that circumstance the engine continues to drive the belt but, of course, inasmuch as the rolling element is not cooperating, the belt eventually breaks. There could also be an issue with the tensioner not applying the right amount of tension. If your friend would like the entire circumstance looked at, with a view toward identifying the cause, and getting any needed parts replaced, plus of course a new timing belt, please simply request timing belt replacement and the responding certified mechanic will promptly address this.