I'm thinking about not talking to my sibling.
Why aren't you going to talk to him?
I have no reason. I just feel like it.
If you really do not want to talk to them, that's fine. Forcing yourself to talk to people is not good for your mental health.
Screw that, I'm not going to talk to him.
While it's OK to get space from your family, it's also great to chat with them. It sounds like you may be having some mixed feelings about your brother, so maybe it will be good to have a conversation with him about what's bothering you. If you don't communicate with him, you'll never resolve the issues between the two of you.