The reason that he's the boss is because he earned that position

i don't quite agree with this. there are many ways for someone to earn that boss position and isn't actually representative of his ability. In my understanding in jobs like this everyone needs to focus in their jobs cause customer needs to be served and don't need to care about anything that's going on the inside.

After that if someone has issue with the boss, the way they worked, a proposition to make they should talk to each other using arguments and state their opinions. If he is right he is right if he is wrong he is wrong. Now if we add yelling in that either in front of customer or not then that's completely wrong.