family sharing

Hi when my partner got a phone, it was originally set up on the family apple id so he could access apps and itunes. After getting to much information shared such as contacts, it was set up with his own apple id but then still signed in on the family id for media and purchases. Now we want to purchase apple music. Would it be better to sign his device out of the family id and set up family sharing so he could access apps and music and keep everything set up or is it best to keep it as is? I don't really know much about family sharing. Thanks for any input!