Panel 1: Phil does the very futile thing of trying to get Elly to stop arguing about an issue she feels strongly about only to be told that there is no argument.
Panel 2: What they're doing is talking about his calling dibs on something that's hers because she was there first only to have him say that she doesn't automatically get a pump organ that will collect dust and get damaged by idiot children.
Panel 3: Elly tries to remind him of her belief that she's just this little servant girl forced into bowing down to a selfish and cruel hedonist kid brother who delights in her misery because chauvinism. Phil tries to tell her that she's talking bullshit because she never wants to admit that their parents kind of hate him for taking forever to settle down, spending three years living in sin and not making more Richardses.
Panel 4: This leads to the air hostess offering Frick and Frack binding arbitration.
Summary: What's lost on Phil is that the only way he's gonna ever stop being seen as the bastard kid brother who ran roughshod over her all her life is when Elly passes away. Nothing in his nature allows him to see that Elly can only see what she ain't got.