Before my Mum was diagnosed with dementia, (but perhaps there were signs) she got new curtains delivered and unpacked them ready to hang. Then they somehow went missing. We all searched the house from top to bottom, but they were nowhere to be found.
At the same time, my Mum had had carpet cleaners in, and my Mum had given them cups of tea and biscuits and chatted with them as she always does with tradespeople, getting their life stories and woes. She learned that one of them had a son who was getting married, but he didn't know what to give the couple as a wedding gift. Apparently, he wanted it to be something nice, but he didn't have a lot of money to spare. (Yes, our alarm bells were ringing at that too!)
So Mum concluded that the carpet cleaner must have taken the curtains as a wedding present for his son. Privately, we were sceptical - I mean, curtains as a wedding present? But anyway, it was a story that meant we could stop looking for them.
In the summer, the next year, we found the curtains, in their opened wrapping, outside in a garden seat that was also a storage chest. How did they get there? No-one knows. By the time they were found, my Mum had got new curtains.