Adult Siblings - How many are not on speaking terms?

[Sunbreak]

I only have 2 siblings. My sister and I get along fine, although not real close and we live in different states. My brother doesn’t connect with anyone - not cousins, not me or my sister. He didn’t even go to our parents’ funerals and he lived in the same house with them. We think he has some type of mental illness based on other behaviors, but there’s nothing we can do since he refuses contact.