I don’t think this is about salaries, I think this goes back to the very fundamentals of childhood and is about how we all compete with our siblings to a degree for the same amount of love, attention and validation from our parents.
Your sibling has done everything wrong and elicited huge amounts of love and attention from your parents.
And you’ve done everything right and have perhaps had less love and attention and validation from them.
That is bloody infuriating for a start!
(In reality, they certainly love you as much as your sibling op, and probably love you more, but in a way that’s much quieter, because you haven’t caused them the same degree of heartbreak, and they don’t show this love to you as much because your sibling has taken up so much “air” time, they need to appear to be “fair” as parents and the parental instinct is to fight fires with whatever child is in crisis at the time and put their attention there.)
I think you have probably been forced to always be the responsible one, and to align yourself with how your parents feel … and you probably have found that their emotions for your sibling are probably not that different to your own …. in that they love them but hate their behaviour and they are probably on tenterhooks waiting for your sibling to screw up the next opportunity but desperately hoping they won’t and out of loyalty, they are of course not saying that to you.
And I think your rage is understandable op in this situation if it has never been spoken about openly within the family. Your op indicates that there has been a lot of covered up emotion and lack of openness. To a degree your parents are covering up the hurt that has been caused to them and to you while this has been going on. And you haven’t had any say or control over it and yet it has affected you deeply.
You probably don’t want to put more pressure on your parents but I think it’s ok to gently remind them that you also value their love, time and attention. And maybe create a few opportunities this summer where you can be together without your other sibling and talk to them honestly. Tell them you are feeling mixed emotions about this.
I think also the other helpful question might be “what purpose is this emotion of rage serving?”
If you explore that, perhaps with the help of a therapist, you might find that its a sign that you need to put some boundaries in place, that you have been drawn in to a family collusion of sorts where hurts have not been sufficiently acknowledged and you now need to draw a line for the sake of your own mh. And it may be a sign that you need to take a step back from your parents and your sibling while they continue to engage in this endless alligator roll of emotion and fire fighting.
Your parents evidently can’t step back from it yet until they decide to do so, because it’s their job to keep trying until they decide they no longer can.
But you don’t have that obligation op. You are an adult and you can free yourself and step back a little and tell your parents that you are doing so. You are allowed to acknowledge the hurt that has been done to you in all of this. And you are allowed to draw a line and say that as far as you are concerned …. “enough is enough”.
If your sibling ever gets to the point where they are fully recovered they may one day acknowledge the hurt that was done to you during your childhood and the huge strain they put on your family as a whole, but that sounds a long way off as yet and you are allowed to step back from them in the meantime.