One of the most bizarre arguments with a student I have ever had was with one of these students, who asked me where I had my medical training. I explained that I've never had medical training, to which he insisted that, yes, clearly I have because I know too much about medicine, and where did I get it?
Your student is learning, growing, and experimenting. They may have difficulty in balancing entertainment with work, and it is not uncommon for students to struggle because they are taking too much time with entertainment ("partying" to use the vernacular). They may also be experimenting with things that are a concern to you (alcohol, drugs, sex). It's important to help your student through this time, without becoming overbearing.
Unfortunately, the approach of memorization in classes is reinforced by educational requirements set forth in 2001 with the "No Child Left Behind" act, which relied on standardized testing of students for federal support of school systems. Memorization of facts is easy to put into automatically scored exams (true or false, or multiple choice questions), making it the easy choice for large numbers of students taking exams. Unfortunately, it is far more challenging to create questions that can be mass scored that requires actual synthesis of knowledge.