My husband is the second household member. But when he tries to listen to Amazon prime music on his phone it says he has to buy unlimited. I will not allow him just open up Amazon prime music. Is there something I need to change
Not all Prime benefits can be shared. Read this help page - https://smile.amazon.com/gp/help/customer/display.html?nodeId=201910370
Your husband might try a different music service if he doesn't want to sign up for Music Unlimited.