In episode 12 of Tokyo Ghoul:re,
Kaneki gets his memory back.
However, I didn't understand the dialogue "well sleep, Haise" before that, and the following event regarding Kaneki's memory.
What actually happened?
The metaphor is that Kaneki is putting Haise to sleep, as now Kaneki has taken over by regaining his memories. Haise will never come back, as he has become a part of Kaneki. The 'cliffhanger' now is how will Kaneki act around his friends that Haise made, and what will he do next.