Why are worldly relationships seen as less reliable for spiritual progress compared to the Guru-disciple bond?

Chapter 45 clarifies that while worldly relationships have their place, they cannot be fully relied upon for achieving the ultimate spiritual goal. The text suggests that family members, including parents, children, and spouses, have affections and concerns tied to the material world. For instance, a son may focus on inheritance, and a wife may mourn her worldly status. The text posits that if people cannot fully help in worldly life, they are even less equipped to help one achieve the spiritual goal. In contrast, the Sadguru is presented as the solid embodiment of Brahman-consciousness, the one who can guide the disciple toward the eternal, making the Guru the only truly reliable companion for spiritual liberation.