From the article: "It turned out the 68-year-old forgot all about his secret stash — amounting to $100,000..."

It does not state he had forgotten only where he had put this cash, it says he had forgotten all about it, period. No where does the article state that he knew the money was missing. No reaction of  alarm. Instead, the reaction was surprise.

So OK, I'll pay attention. Meanwhile, you take a remedial reading comprehension course.