she filled out a form that specifies it is to be split 4 ways when she dies (1/4 to each kid). Hopefully that is sufficient?
In my family, the conflicts weren't over easy things like dividing up bank accounts.
One example: Before my grandmother died, she moved into an assisted living facility and one of my cousins (and her family) moved into grandma's house (not free, but at very a very subsidized rent). When grandma died, the will specified that the house be sold and the proceeds divided between her children, but the cousin's family tried to argue that cousin should get to keep renting the house, because grandma had been letting her live there, and they were going to be homeless without it. Are you prepared to kick out a family with small children just so you can cash out of a property in accordance with the will? Parts of my family still aren't speaking to each other after this debacle.
Another example: My other grandma spent the last few years of her life living with the wealthiest one of her four children, in their big fancy house. Her assets helped pay for building an integrated MIL suite, and then supporting the household for all of those years. When she moved into a nursing home, her assets had to be depleted to zero to qualify for medicare and she died penniless. The one daughter she had lived with was left with approximately a half million dollars in improved real estate value as part of her primary residence, that grandma had paid for, but which was technically not one of grandma's assets. The other three kids got nothing of value, other than picture and keepsakes. None of the other siblings were prepared to cry foul, so the one daughter who was already rich was the only one who got anything of value from grandma's assets and everyone sort of swallowed hard and moved on.
These sorts of complications are hard to foresee when you write a will, because neither of them were issues until the end-stages of life.