Re giving your things away, I was 18 but still very upset when my mother got rid of two treasured books (among others) when they moved after I’d gone away to university. One of them - a far from common non fiction book - was published in the late 1800s and had been given to me by a grandfather.
By some miracle, many decades later dh found an identical copy on some 2nd hand site.
As for my poor dh - his mother gave almost his entire treasured collection of Dinky Toys to a neighbour’s child, again without after he’d gone to university - and again without asking. They had a big house - it wasn’t as if they didn’t have room.
I still don’t think he’s ever quite got over it!
Worst I ever heard of was on MN though - somebody’s MiL who was supposed only to be feeding the cat while they were away, took it upon herself to ‘declutter’ her son and DiL’s bedroom, by throwing out DiL’s complete collection of (IIRC) Chalet School books, plus a lot of memorabilia, personal letters, etc.
How could you ever be civil again to anyone who did such a thing? Of course when confronted the MiL turned the tap on - ‘I was only trying to help!’, etc., and made the DiL out to be the baddie for making her cry.
IMO under the patio would have been the best place for that MiL!