Venting about the mental health of youth

Not sure where to put this or if this is even the correct title but for some context, some family has been staying with us for the past three months. (Brother in law, his girlfriend, and their 5 kids). My husband is black/puerto rican, I’m white, and our sons are mixed (one is fairer skin than the other - these details matter to the situation) my brother in law is also black /puerto rican but lighter than my husband and his girlfriend is black. They have two darker skin children (hers) and three fairer skin children they share. I say all of this to say that one day, their middle fair skin child asked me if I take my older son (fairer skin) out of his car seat first before my other son because his skin color is the same as mine and honestly, it broke my heart that he thought this. I told him I take him out first only because he is on the passenger side of the car so I get to him first and his brother is on the driver’s side so their dad gets him out. I also reassured him that the color of everyone’s skin has NOTHING to do with anything at all and that we are all human. This is not the first time I have heard their boys disagreeing on things solely based on color. Idk what they teach their kids in private but personally I believe both my brother in law and his girlfriend tend to weaponize their kids against each other because he biologically only fathered three of them. I say this because I’ve witnessed the fairer skin child get different privileges from both parents than the darker skin boys and he has said aloud that he is “white” because he’s lighter than his brothers. Hopefully this all makes sense but this happened over a month ago and my heart breaks for all of their kids every time I think about it. 💔