Antagonist analysis time!: David Nelson edition (Nick's older brother)
I wouldn't be surprised if Stephane Nelson was more homophobic when the boys were younger. It would explain why David keeps referencing variations on "Dad's not gonna like this" in reference to Nick and Charlie.
And it would make a lot of sense. It reminds me of the quote from I think Bruce Springsteen about how when we miss our fathers, we try to emulate them because it's our only way of feeling closer to them. I think David emulates some version of his father he misses. You see that he behaves that way for him either way when he consistently references him and brings him into the conversation nearly every time he's homophobic or biphobic:
From bringing up "I bet you haven't told Dad yet, have you? Oh my god, image what Dad's gonna say" when he's not there to a direct seeking of approval in "Dad agrees with me" when he's there.
When Nick says he's bringing Charlie, he asks if he can bring someone too. When the whole family comes, he knows it'll be about that, so he tries to take control of the conversation that he can't stop from being about Nick and Charlie by attempting to guide it (and out Nick) himself.
It's then after Nick draws focus by saying he doesn't care about their dad's opinion of him and leaves the room that he says he's "making a scene". Because he's taking their father's attention away from him.
David views Nick as competition. Competition for their father's attention, which is in short supply anyways. He doesn't want to admit that it being in short supply is bad because he doesn't want to blame his dad, so instead, he blames Nick for "stealing" the attention. Because then he can believe that if only Nick would stop "making a fuss", his relationship with his dad would be sufficient and the only thing stopping his dad from giving him the appropriate amount of attention is Nick, not his dad.
And not only is it only after Nick draws attention away from him at dinner that he makes this "attention-seeking" comment, but it is also only after he sees his dad trying to leave without saying goodbye before then in the same conversation forgetting where he goes to school (a wonderfully performed one word line, also. it clearly takes all David's strength to even admit he's wrong enough to correct him and say "Glasgow"). It's only after the window of attention to receive closes completely that he goes on his full rant on the phone, and it's only after his perception of his father has been made fragile with Nick's comments and his father forgetting things about him that he now has to re-emphasize the narrative he tells himself tenfold to make it secure again.
And one more pertinent thing he says on that phone call is that Nick is being over-dramatic. Because if Nick isn't being over-dramatic when he says that their Dad doesn't care and it's messed up for him not to visit more, then that means Nick is right. And if Nick is right, then David has to admit to himself that his Dad is in the wrong, that his Dad is hurting him. That his Dad doesn't care enough about him. And he can't do that.
One last thing he also does is blame Charlie. He says on that phone call that Charlie must be influencing him to be more attention seeking. He also uses the phrase that season "turned my little brother gay" and continues into the next season to describe Charlie as attention seeking. Because he can't truly allow himself to blame Nick either.
His inability to truly blame Nick is the same reason that when we meet him he's teasing him about what he thinks is a girlfriend texting him. He's overstepping and we know from Nick he's been a jerk in the past as well, but the behavior he's exhibiting in teasing him about a girl is something you only do as a misguided attempt to get closer to someone. He's missed Nick too.
It hurts to blame his dad, so he blames Nick. But it hurts to blame Nick too...so he blames Charlie. Charlie who he doesn't know. Charlie who doesn't hurt to blame. Charlie who thinks his dad would blame. Blaming Charlie isn't admitting something he's lost. He hasn't lost Nick, but admitting that takes us all the way back to admitting that he has lost his father. If Nick has become an attention seeker who ruins everything by stealing the attention from their Dad that would be his, that he would visit more, would care more, would remember more, would come to Christmas if it just weren't for Nick. But of course, deep down, that's still his little brother. His innocent little brother so anything that's "caused" his Dad's behavior must not be his fault either. Yes. It must be Charlie's.
It's Charlie's fault Nick is taking his Dad's attention away from him and in season 3, do you know what else is Charlie's fault? That Nick's attention is taken away from him. He only calls Charlie an attention seeker for having an eating disorder on Christmas. Christmas: the day that his dad doesn't show up, in the conversation Nick started with "you know Dad's not coming". He brings up Charlie out of nowhere in direct response to Nick saying their Dad won't come because he makes empty promises.
His dad isn't there; he doesn't wanna blame his dad, but in his dad's absence, he also misses his brother - who's been preoccupied recently with Charlie. There. It's all Charlie's fault. Not Dad's. And when he needs him, not Nick's.
Really, I just realized that that phone call didn't happen for no reason. He was upset enough about dinner that he needed to call someone and vent. At the end of the day, that's what happened. He wasn't making a snide comment. He went somewhere private and called someone he trusted to talk at length about what had happened. That isn't just about Nick being bi. But he couldn't bring himself to admit that he was actually venting about
"David, you have not grown into the man I thought you would become."
And that is also why I would like to shout out the character and Alice Oseman for the inclusion of Nick's Mom calling not David but Stephane out when he tells David "you have not grown into the man I hoped you would become". Because she's right. A brother saying that to his brother and a father saying that to his son are NOTHING alike. She knows immediately how deeply to the core that will cut David and that Stephane didn't even consider it. It is a great "who's the real enemy" moment that reminds us "this is not the non-homophobes versus David, actually. It's a family with a homophobe inside it protecting themselves from the man who left them. It's a mother protecting her children from him." And, as she said, he has no right to side on their disagreement because he has "not been a parent".
He has no right to choose sides when he has no consideration for the utter desperation they face for him to pick theirs. To pick them.
Every bully is just someone desperate for approval. From peers, from authority, and saddest of all: from parents.