you'll have to take a look on her phone or ask her.
we get this sort of question almost on daily basis. the problem is that there millions upon millions of apps out. so unless the app in question is something popular like facebook or youtube, trying to find out what app is what just on its notification icon is like searching for that infamous needle hidden in some random haystack.
most of these inquiries almost always go unanswered. you will only get guesses from us. you might get lucky and someone here might recognize it, but i would not hold my breath on it.