Today, my father forgot how to double-click.

Not only did he forget how to double-click, he is sitting there insisting that he's never done it in his entire life. One of the single most basic things in Windows for the last 30 plus years, and he claims never to have done it.

I'm not handling it well. This is scary to me, and he's demanding to know what the big deal is, and still insisting he's never done it.