be careful OP. secrets this big can cause people to do horrible things when the truth comes out. make sure you are safe if your going to talk to him. put your safety, sanity and happieness first.
men have killed there gfs/mistresses out of pure desperation to cover up secrets so please proceed with caution.
Thanks Michelle, You clearly have a good heart, and I appreciated your concern and advice. I am miffed that I had to find out about it this way, and without a doubt he has a lot to explain. This is really an issue between him and his sister, and I want to stay out of it. I am hoping they resolved all issues years ago, and never told anyone because they considered it to be a private matter between the two of them.