Tracking cell phone in Belgium from the U.S

[How to]
#1

In the U.S. on our iPhones on AT&T there is an app called “Find Friends” that allows family members to track each other’s location.
One of our family members just moved to Belgium and is on the Orange network.
Is there a way for us to track the location of her cell phone?
She is OK with us doing this and would know we are doing so.

#2

Is the ‘Find Friends’ app AT&T -only?

If it is, I suggest switching over to the ‘Life 360’ app.