[reginald78]

Can't comment on Google specifically but hidden scrollbars mean I often don't realize a dialog has scroll bars until I reach out into the dark edges to find what I hope is there. Microsoft will even harness this as a dark pattern to hide options they don't want you to choose.

Perhaps your dad simply expected to scrollbars to be visible like they initially were.

[ben_w]

This was before scrollbars got routinely hidden like that, it was in the mid to late 2000s. He retired in the late 90s.