Kids that have this kind of adult conceptual reasoning, though-- if they also have equally advanced social skills, it's really, REALLY easy to forget how young they are.
People did it all the time when my DD was little. They'd suddenly look at her and really SEE her, and I could watch the penny drop when they connected what had just come out of their mouth with her age and CRINGED inside.
Like the (wonderful) children's librarian that discussed a really awful anaphylaxis fatality in front of DD, then 5 or 6 yo. She took in every word-- the librarian was HORRIFIED when she realized, but I reassured her that I understood that she'd meant no harm. Luckily, we had already opted to shelter her from pretty much nothing... but-- this is also a good argument (IMO) to NOT shelter this kind of child; others WILL tell them things that children should not be processing. The better strategy (IMO) is to let them see the world more or less unfiltered, and convey the message that NOTHING is off-limits for discussion with you as parents.
We've wound up having some very strange conversations in light of my DD's age, but the bonus is that she doesn't fester on things that bother her in the media-- she talks to us about them. Precocious kids in particular, it's almost inevitable at some point that they'll be handed something that they can (cognitively) understand, but emotionally cannot process or come to terms with.
This isn't that extreme, of course. I'm just pointing out how even really good professionals who are used to working with children can very readily forget how old a HG+ child (with this particular profile) actually is and say things in front of them that they should not. We've handled this kind of situation with a blanket; "This is really too 'big' a responsibility for a child. It's an adult responsibility, this choice/decision-- so your parents are in charge of the decision-making here. Okay? We'd like to know what you think, though, as we talk it over."
That lets the child know that s/he isn't in charge completely (that YOU are) and that you still value his/her opinion because it concerns him/her.
