Calling all facebook users

I goto my boyfriends Facebook profile through a friends facebook and see he has 6 friends that pop up and they show up every time I’ve gone on the app to check on him. As of recently it changed a friend or 2 but I’m wondering do those top 6 show up on the profile because those are the ones you interact the most or what? Cause im really confused and I see about 4-5 girls on there and I’m not sure how facebook works so please help me out here