”Sibling small-talk” when sibling recently passed

My spouse recently lost her only sibling, very suddenly and out of nowhere (young healthy man, freak accident type of thing. No funeral/ ”public announcement” was ever made as he was quite private). And while our friends know about it, random people and less close acquaintances abviously don’t.

Those we run into that remember her brother will ask how he is doing etc, new people might use ”do you have any siblings” as small talk. Every time, I see my spouse becoming very undone by this, it can shake her for a very long time, and obviously, having to answer to people who knew him that he is now dead will make everyone/everything very dark, but it’s even worse with the new people.

If they ask ”do you have any siblings”, I can see her trying to conceptualize the answer, I guess we never train for these type of situations… so like will she say ”yes but he’s dead”, or just no and skip it to ”keep the mood light” (think afterwork/birthday party etc), but I think to her that would feel disrespectful to his memory, to act like he never existed.

We and the late brother are (were) all in our 30s, so it’s not yet an age where people expect siblings to have been passed. But I know of course that it happens.

So I’m asking, is there anything I can do in the way of making these situations easier for her? Would jumping in and breaking the conversation be super bad, I know subjectively that she doesn’t like to talk about it, and also it will make her feel really bad, but I don’t want her to think I just want to gloss over this.

I have, of course, discussed this with her, but I’d love to hear point of views/ experiences from people who have gone through this, because I feel there may be something botyh of us are overlooking. Thanks a bunch.