Because Chloe Turner was in a bad mood, Cherish thought that, as her sister, she should also show some concern for her.
Cherish was no longer attached to the past.
After all that had happened on Mount Heng, with Bob Turner dead and Chloe Turner in this state, Cherish couldn't just stand by and do nothing. At the very least, she had to make Chloe cheer up, since the Turner family needed her.
As for the matters between her and William Griffith, who didn't have a past? Since those things had happened, regardless of what kind of existence they were, they had to be resolved.
After Cherish returned to the apartment, she did laundry and cooked.