Another Old Regret?

I didn't get much sleep last night. I spent most of it tossing and turning. It must have been around 5am when I finally fell asleep.
What dreams I had, I can scarcely remember. One scene, however, stands out starkly in my mind. I came home to an empty house, as the rest of the family had gone out to dinner without me. Not an uncommon occurrence back when I was working. I'm not above cooking for one, but in this dream I decided to go out to eat.
The restaurant wasn't much more than a white booth with a kitchen inside and some tables outside, covered in checkered plastic tablecloths. The kitchen staff was entirely latino, as it can be in these parts. They responded to my order in spanish, and spoke among themselves in that language.
Looking back, there was a young man with black rimmed glasses sitting at one of the tables. I didn't have to be told to know he was my half-brother. How I knew was something I didn't understand. There were no introductions. I sat down next to him and he asked me about our father. He wanted to know what kind of man he was.
So I told him. He wasn't fazed at all, a smirk appearing on his face. It reminded me of my father's, and I felt a strong inclination to punch him. I can't remember at all what happens next. We sat and talked some more, but I cannot remember the words or anything about what was said next before I woke up.
What disturbs me most about this dream is, a few years ago, my mother was approached by a woman. She allegedly had a daughter with whatshisface, which would make her my half-sister. Apparently she wanted to meet my siblings and I. My mother turned her away. I had the feeling she struggled with herself over whether to tell us or not, but she had in the end. She made her feelings quite clear, that we're all the family we need and didn't need anyone else. She asked us if we really wanted to meet with any of his other children. My sister answered in the negative right away, speaking for all of us. I had my reservations, but I knew it would only upset my mother, so I kept quiet.
Still, it bothered me for awhile. I had a half-sister out there. How much does she know? About him? About my family? She wanted to reach out, why? I don't know if there would be anything sinister in that, though with anything concerning my father, I have to be cautious.
Hm. I just remembered almost a decade ago my mother mentioning my father possibly having another son out there as well. I don't think he would be as old as the young man in my dream, but there is the possibility that there is one out there.
I feel a strong urge to talk about this with someone. I could go to my sister, but she'll doubtless report to my mother about it as close as they are. If I'm going to do that, I may as well speak about it to both of them directly. Even so, it's not going to be a pleasant topic of discussion.
Why couldn't that bastard have just kept it zipped?