If it weren't for the Chaos-level strongman Hongyue, Zhou Heng would definitely not agree to Liu Shishi's request. Then again, if Hongyue weren't around, Zhou Heng wouldn't behave so outrageously, and Liu Shishi naturally wouldn't come to him.
Helping Liu Yun'er is helping, and helping Liu Shishi is also helping. After all, he has already offended a Grand Marshal like Lin Wubing; offending an emperor at the Black Cave level doesn't seem to matter much either. These big figures only have their eyes on the "mysterious strongman" behind him for now and won't personally make a move against him.
This is an unspoken rule: matters concerning the younger generation are to be resolved by themselves, as long as it doesn't lead to a life and death conflict.