My H is the oldest of three siblings.
SIL still lives at home and BIL has moved out but literally lives next door and has dinner and goes around to in laws daily.
We have a family and live 10 minutes away from everyone.
BIL and SIL are nice enough but even though supposedly a close knit family, they treat us like strangers in my opinion. Never really giving away many details of their own business, never even sharing as much as any kind of real information or thought with us. Never levelling with us, on the relationship with their parents.
My H and his father are in business together and this causes some friction in the family, as you can imagine. BIL and SIL never ever let my H know that they understand the difficulty in working with family and level with him about it, but would rather always clearly take sides with PIL. There have been some upsets and whenever BIL and SIL have been around, they very clearly and loudly took parents side. They've never once said to him that they understand the difficulties faced. But if anything comes up, you can tell they think the parents are always right.
We don't discuss our issues with PIL with H's siblings and just get on with it. However, there have been a few times over the years where they've just happened to be around.
The relationship with in laws is complex.
Now onto my point that PIL discuss our business with their other kids, but they don't discuss their kids's business with us. They know stuff about our finances / our plans etc. but we don't know anything about them.
Why do they know stuff about finances ? Some of the finances are unfortunately interlinked because of the business and it can't be helped sometimes.
They seem to express opinions about things we do / decisions we make, as they have access to this information, but not from us.
My H is clearly the black sheep in the family and according to MIL it's because I'm a horrible person of course. I once did raise it with mother in law that sometimes she could discuss her grievances with me without a massive audience. This was after I had my first baby and she was hyper critical of everything I was going, in front of everyone and I felt embarrassed. I asked her to please next time, either keep it to herself or take me to one side and not discuss in front of everyone. She absolutely lost it because she felt like I was calling her other children strangers.
I want my H to raise it and if he won't, I will. No one should know our business from PIL.