X's half sibling was born to his first-mom, and she's parenting. We've told X that she was going to have a baby who is his half sibling. I'm pretty sure he really doesn't grasp the concept given that according to him, his brother lives in our house (Baby A). But, I figure that we need to approach events like these with matter of fact talk no matter his age. Besides, we see C somewhat regularly, and I'm guessing we'll be meeting her baby as well.
There you have it. It's getting more complicated.
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