Tear meets smile
The Father is looking for his phone and feeling a little bit disoriented. Or maybe it is the fact that he is looking for his phone that makes him feel disoriented. He never has to look for his phone, it is always with him. He's in an excited, calm, refreshing, nervous, anxious mood as he calls out to his kids "wait for me, I need to find my phone".
The kids don't really know what is going on. To kids, things are not evaluated at the "good", "bad", "normal", "not normal" way that they will eventually think of things as adults. This is not to say kid's feelings are simple or less complicated. In fact, they are more complicated than the adults for they haven't learned to shut down or funnel emotions yet. Emotions are raw and joyous and painful and numbing and exciting. It is the Father who is cut off from his emotions. He's been cut off for some time.
The Father can't remember what it was or when it was that the emotions got cut off except that it was long ago. It wasn't a single event that did it. No, it was more like multiple small wounds all bleeding at their own rate and no amount of love, temptation, distraction, seduction, inebriation, or endorphins could close the wounds. Eventually the Father's emotions bleed dry.
So this feeling of disorientation the Father had while his kids played video games wasn't disorientation at all. It was his emotional heart starting to beat again. Tick, tock. Tick, tock. Tick, tock. The only question is whether he would notice. The tear meeting the smile indicates he might.