Help with adopting a sibling

Do these children even know each other? Have they ever lived together? I wouldn't let them guilt you into this. The boy is 5 and unless he's had some significant relationship with his sister, someone else put the idea in his head that this is what he wants. I would NOT do the phone call with the boy. If this isn't what you want and you were not planning to adopt, tell the case worker, NO. You're concerns are valid.