| Quote #1
Here we can see clearly that Jamie and Edmund have very different roles in the family. Jamie is ten years older and, from the beginning, he was expected to treat Edmund like a baby while he was becoming an adult. You might even sense here a touch of resentment, that Jamie has had to deal with Mary for so much longer than Edmund.
| Quote #2
Why, exactly, does Edmund give up his suspicions that Mary's back on drugs? Perhaps because real tenderness like this, which doesn't seem in any way mechanical, is in short supply in the Tyrone household. Edmund hasn't been nurtured all that much, so when he does receive affection, it's really effective.
Even more importantly, why does Jamie set his face in embittered, defensive cynicism? Sure, on one hand he's upset that his mom's back on morphine, but is that why he's "embittered"? Isn't it possible that he's jealous of the affection Mary's giving his little brother? Tenderness is in short supply around this place, and we know that Edmund gets pretty much all of what there is. In fact, there's no point in the play in which either parent is really, genuinely tender toward Jamie, and this moment suggests that he resents the lack of family support in his life.
| Quote #3
Are these really the reasons Jamie ought to respect his father? Maybe if James were a neighbor down the street – but are hard work, mortality, and monetary support the basis of a stable, respectful relationship between a son and his father? Note that Mary never uses the word "love" here. There's no question of Jamie loving James or vice-versa. Mary is, of course, right that Jamie's rude to his father, but they fail to get at the underlying issue here – Jamie can't respect and admire his father all that much because he knows him too well. These superficial traits like work, age, and money don't define who James is as a person, and so they don't define the person Jamie refuses to respect.