Nightmare fuel and misery rolled into one...Wow I never heard of When the Wind Blows until this discussion, and I just looked it up on Wikipedia, pure nightmare fuel of a movie.
Heck, not just Disney. My grandfather told me when he was a kid in the late 40s/early 50s, most of the live-action pictures that got shown to families wouldn’t have been considered suitable for kids now - plenty of violence of various kinds.Also we must remember that the early Disney animated movies had very dark and scary moments too at a time when there was no such thing as "kiddie movies".
Of course, kids being kids, he said that himself and his friends had liked it that way
But yeah... IIRC, theatres didn’t really take age ratings etc. seriously until Night of the Living Dead.