Hiragi-san: What makes a cozy family with a secret believable?

The anime announcement introduces Shota, an orphaned boy taken in by a family that keeps a secret. Without having read the manga, I'm drawn to that mix of welcome and mistrust. I'd like the routines—saving him a seat at the table, for example—to build affection over time, so that discovering something strange in the house carries more weight.

Do you prefer the secret to gradually alter those small gestures, or for the welcoming part to serve as a respite between unsettling moments? I'm talking about expectations regarding the premise, without manga spoilers.