a decision, not a duty

Siblings don't have obligations to each other merely by virtue of being biologically related.

Those obligations arise only from a proper relationship with them. 

With deeper ties come expectations. 

Because you find your interactions with your siblings unpleasant, you already have one reason not to go on with a relationship.

So far, they haven't asked for your help or point of view. 

By limiting your interactions with them, you might feel a lot better. 

Whatever assistance you provide will be a decision, not a duty.

https://www.nytimes.com/2023/02/20/magazine/autism-friend-ethics.html