Sorry this happened. So glad you spoke to your child about boundaries and that some questions may be overly personal.
Sometimes when we are annoyed as parents it is because we were unprepared for the unexpected event or obtuse question, and did not have an answer ready. Parents may wish to have a simple generic sound bite or two, or even a quick mention of a book that addresses the subject.
For example:
When asked whether the sibling attended the gifted school, a generic statement that "kids are so much more than an IQ score... interests and learning style help determine the best educational fit" may be an answer which would deflect focus from your child and also spur the sub's further growth about gifted education.
Or "That's a great question (interesting thought). The book XXX addresses that well. I think you'd like it."
