Unfortunately cases don't guarantee protection. They just reduce the risk. I'm sorry to hear your son got unlucky. All you can do it repair it. Unless you bought a coverage protection for this sort of thing it will be out of your pocket. There's no way to prove it was a manufacturing defect that caused it to Crack without expensive NDT an that's not even a guarantee. You can get it repaired via Koodo or shop third party repair options. Most cities hav repair shops for phones that you can browse around. Get lots of quotes. Alternatively you could buy a tool kit and screen an replace it yourself with tutorials online and teaching yourself. It's cheaper but you need to learn.