the "death" vibes you're getting here are probably feelings of "she's no longer here" / "can't race against/with her anymore"
irl people wanted to have biwa and brian race against each other and this is referenced in the story as well. iirc this is also referenced in-game where in brian's...
was anticipating this chapter when we saw biwas time trial ghost. if you know the IRL lore this chapter becomes more of a treat since the commentary is based on the IRL race commentary but its juxtaposed with the depressing vibes of brian chasing something that's no longer and can no longer be...
In addition to Biwa Hayahide and Narita Brian, Dream Journey and Orfevre are also depicted as siblings in game. IRL they shared a mother AND a father - Oriental Art and Stay Gold (who is also in the game)