Libre vs Dexcom. Anybody used them both?

The key shortcoming of the Libre is that it won't hypo alert someone's phone like Dexcom. But I understand that it will if you buy the Nightrider and stick it on top of the sensor and use Xdrip. But will it alert my wife's phone too, like Dexcom will? My friend's kid uses Dexcom and it alerts the kid and the dad if he's hypo, it lets him see all the data on his phone when the kid's at school.