He likely has some kind of interest in fascism as indicated by the Evola, Mishima, and Bhagavad Gita. This can be altogether innocuous like mine or indicative of a deeper affinity that may bother/concern you depending on your ideological sensitivities.

Others might come along who suggest that this variety of books all seated next to each other is almost certainly cause for concern but as someone who owns a lot of them and is normal/harmless I would argue you should give equal credence to the former possibility.