It's not about distrust, but rather that everyone around them had only just settled in not long ago, and they were all still in a period of adjustment and adaptation, given his understanding of the Tang Family's actual home life.
No matter which family was entrusted to care for these three children, he feared it would bring a slew of trouble.
Right now, Qu Guo'an was busy with a bunch of things and didn't have the energy. If later on, due to the children's affairs, trouble started brewing at home, with people coming over to gossip every day, he was afraid it would drive him mad.
Once Ji Dong figured these things out, he simply closed the door, determined to fulfill his caretaking responsibilities before the group captain's couple returned.
