Need help about "Linked Reference" for page

I have a component hierarchy for a page as shown
We have
‘grandfather block’
‘father block’
‘son block’

my question 1:
How can I see a sibling block of a page?

In this case, I mean how can I see the contents of another Son Block in the same father Block in the ‘Son Block’ content?

my quetion 2:
When I click on ‘father block’, it shows 'son Block 'is folded, how do I make it expand?

Do I need a Query for this purpose?

Thank you to everyone who came to read!
If anyone can help me with this, thank you very much!
Thank you!