I usually just lurk on these forums, but this time I thought I'd add my story.
As another member commented, I too have a disabled child. He was tantruming badly when we got home one day, several years ago. Rainbow, our then 3 yo GSD was with us in the van. Normally I grab the leash, let Rainbow out of her crate, then grab my son out of his seat, grab Rainbow's leash and head in.
This time I was focused on dealing with the head banging, flailing and generally difficult behaviors so I told Rainbow to stay, left her sitting in the van, out of her crate with the side door open, planning to come get her as soon as I got my son inside.
Needless to say, I ended up forgetting about her and a good hour later thought to myself, where's the dog? Suddenly realizing my mistake, I bolted outside expecting to be on a dog hunt, but there was my good girl, calmly watching the world go by exactly where I left her.
It can happen to anyone 😉