According to Osho, no single event turned him toward spirituality; he felt oriented that way from his earliest memories. His shift was the cumulative, lifelong result of many small experiences sinking into his whole being, not a sudden reaction to a crisis. Still, witnessing his grandfather's slow death in childhood stands out as a formative memory deepening his awareness, though not the cause.
There wasn’t one big moment—he was always drawn to spirituality, and many little experiences (especially seeing his grandfather die) deepened it.