certainly an experience that might alter ones perception of the world. he probably had sympathy for them. and perhaps that sympathy sparked his interest in the native american philosphy'shamanism etc. the dead indians souls are seeds of thought that remained with him through out his life.
Well, Jim's & his mothers' perception would be totally different, to her it was nothing more than seeing an accident on the highway, & to Jim it was more, a mystical experience whether the mystical part ever happened doesn't matter Jim believed it.