Not knowing how long ago, what he did, and if you TRUELY have the facts - not just the one side of the story - this is a difficult one.
How old are the other family members that have begun to make contact? What makes them so different from you?
On the details you have given, I'd be going with the below:
Originally Posted by Pennywise
Tiff took the words out my mouth
You only got one mum and dad
Kiss and make up mate, Sounds like your brother and sisters have???
Why cant you.. HE may have been wrong, but when he goes for good you'll regret it
Trust me