During his last battle with Yotsuyahi, Kaiyochi caught a fleeting glimpse of the Transparent World as he was forcefully propelled upside down alongside Tanjiro.
Paraphrase.
Imagine Mitsuri's family's reaction to her death, I just realized this lol
I just had a realization about how Mitsuri's family would react to her passing.
During his last battle with Yotsuyahi, Kaiyochi caught a glimpse of the Transparent World for a short while when he was propelled in an inverted position, alongside Tanjiro.