tvtropes.com has an interesting entry from its recap of Terra Firma that I want to talk about here. Dad has become Jack in this episode. According to tvtropes, "The sudden switch in nickname or honorific when referring to a character, usually from their family name to their given name, is frequently used to demonstrate a significant change in the relationship between two characters, the desire for one by one party, that they have evaded listeners who require more formality, or that they are Not Themselves. Never using any formal indicators and just calling a character by their exact name is about as common to show the same thing."

I think that John, being totally weirded out about coming home and deeply fearful of doing anything that would hurt Earth begins calling Dad by his name as a way to distance himself from the "Head of Extraterrestrial Relations" -- Jack -- who now represents the Government. John is also terrified that his alien friends and himself will end up studied in some laboratory by his xenophobic planet's scientists. Jack represents all of these dangers to John. Plus, he feels betrayed by Jack's insistence that things have changed after September 11th and John doesn't or won't understand. In addition, John has met "Jack" under deception twice before: once an Ancient posing as his father to supposedly test whether Earth is a place to settle, but it seems to actually be testing John, and again in the Scarren's torture chamber where Jack appears in many personality guises but always as an adversary. He just doesn't trust Dad.

I think the fact that John hides behind pillows, glasses, over-sized jackets, stair rails and popcorn is interesting. When in space and he feels insecure or scared either for himself or his loved ones, he wears gloves. I think his clothing and hiding also show how upset he is about being home. He can't share what he's been through, "hell, they'd lock me up. I'd lock me up." and he can't confide in Aeryn who he still is holding at arm's length in a way that seems hesitant and so cruel because it's so passive-aggressive. When she asks him if she should strip a prowler or a field gun for his people, his answer is, "do what you want" or "no, they've seen enough."

His treatment of D.K. and Laura are also at arm's length which provokes his childhood friend to denigrate John accusing him of grandstanding. But I believe John is trying to tell D.K. and Laura something when he makes a comment about the laptop computers and his question about why PKs turn to goo. He can't say it outright because he's afraid of being surveilled. His paranoia is rampant.

Ben's voiceover throughout the episode is melancholy and lonely. The addition of this voiceover was late in the production to emphasize John's feeling of loss. "Nothing is normal." "Jack just wants Christmas to be normal." "And everything is so Normal." John realizes that he's not Normal anymore.

Humpf McSlow wrote one of the most beautiful and expressive stories about John's trip home called, Normal that is a must read to understand John's mixed feelings: his total love of both his families and his total hatred of himself and what he's become:  https://www.fanfiction.net/s/2749035/1/Normal