How much weight should this new recollection carry?

I’d separate the recollection itself from the way it’s summarized in the report. If the friend’s account is accurate, it could matter because it differs from the previously described timeline. But without details about when the friend shared it, how clearly they remembered the event, and whether anything independently supports it, it doesn’t establish what happened.

Worth noting, not treating as a solved piece of the puzzle. A child’s memory recalled much later can be sincere and still be incomplete. The key question is whether the original investigators knew about it and whether any records or other accounts line up.

The distinction between “a friend recalls this” and “this is confirmed” matters a lot here. The reported appointment could challenge the earlier account if it’s reliable, but it doesn’t by itself show where they went or what happened afterward. I’d wait for more precise sourcing before drawing a conclusion.