Single Iphone with Kids and Parental support. How to Manage?

So..this one kinda stumps me.

My brother's kid was given an Iphone 6s. It's the ONLY iphone in the family. Nobody else has an apple Id, or Mac or iphone.

What is the correct process for managing that iphone from a parental perspective? He (my brother) can't create an apple ID for his child because of age (too young).

Does he create an apple ID for himself and sign himself into the phone? Or is there a way for him to get an apple id and then do family sharing management via the web or itunes on Windows and create a child account (no Mac in the house)?

What options are available?

thanks for the help!