My MIL was one of 6 children. Her brother told her that she was the only one who had ever been there for him, especially since his wife had passed 10 years before. He said he wanted her to have everything, about £20k. They had no children).
He sat at his kitchen table and wrote on a piece of paper "This is my last Will and Testament"...and then he died of a heart attack at the kitchen table!
All of the other, previously lovely, family members, came out of the woodwork and went straight to a solicitor who eventually split it between all of the brothers and sisters, and of the 3 who had passed, it went to their many children, Big Irish families.
The remaining brothers and sisters gained about £3k each but the children of the deceased brothers and sisters had to split the £3k between many of them.
The Irish families were extremely well off, whereas MIL was the proverbial church mouse (poor as). They didn't need the few hundred pounds they received but she could desperately have used all of that money.
The families had previously been extremely close and had often stayed with MIL in London for free holidays, but they were so vile and threatening to her during the whole thing that she was heartbroken and refused to talk to them ever again.
I was shocked at how horrible and threatening they were to her. But Karma bit them in the bums because they gained a few hundred pounds but never got another free holiday at MILs house.
It was an eye-opener in making sure your Will is written and lodged with a solicitor.