Someone said once (I don't remember who or where) that Zhang Shi can't have been very present during Zhao Yunlan's childhood because if his father had constantly switched between acting like Zhao Xinci and acting like Zhang Shi, his inconsistent behaviour wouldn't have rung instant alarm bells in Zhao Yunlan's head. Your write-up reminded me of that, and I'm wondering what role Zhang Shi did play in Zhao Yunlan's upbringing. Was he just the silent observer all this time?
I imagine that Zhao Xinci offered Zhang Shi the ultimatum of "don't interact with my family or I'll rip you out of my head if it's the last thing I do" and thus Zhang Shi was a silent observer of the family drama, with maybe occasional suggestions. I got the impression that Zhang Shi only takes control in extremis, never for the sake of it, and mostly just sits as a live-in advisor.

Yeah, I agree that he loves him, but it's not just that he doesn't understand, it's that he doesn't bother to try. He's very sure that he's right, and his son just needs to see that, and there's that. (Ugh.)
It's very "why are you not like me????" – I suspect he might not be able to truly comprehend Yunlan's viewpoint in some ways, irrespective of the parenthood thing.

I mean, that is approximately Ye Zun's level of emotional maturity ... *g*
Ha, true! We'll also at one point see Ye Zun be baffled why his Hallows mergeration won't work, only to discover that the Lantern is missing, so he can't even count to four. Very left behind in maturity! *g*