Disclaimer:Naruto isn't mine nor is the original 1001 Things It Means to be a Dad book
Being a dad means putting your child's wants, needs, and desires ahead of your own wants, needs, and desires. Every day.
Gaara wasn't a selfish man. He just spent most of his life not knowing how to deal with people. That was understandable right? You live the first fifteen years or so of your life alternating between having everyone afraid of you and you being afraid of yourself and social skills get pushed back. Once he learned how to care, he did his very best to make sure his family was happy.
He went to a strip club with Kankuro once. He didn't have a very good time but Kankuro did and way deep down they even bonded. He watched a show with Temari once about wealthy woman living in a rich part of some village who wore expensive clothing and complained about running out of alcohol. He didn't like that much but at least he got to spend some time with Temari. Sometimes Neji enters his "destiny-mode" again and makes Gaara read big dense books and while Gaara hates them it makes Neji happy.
So when some baby book decided to expose him to the fact that babies need classical music in order to grow he went out and bought an anthology of various classical music composers.
Zen better grow up to be the top of his class because if isn't he is going to pay big time.