<human>: My mom just called me and let me know that she was changing her life insurance and will. In the event that both of my parents pass away at the same time, all of their assets will become mine and I will be asked to divide this money up between my sisters and I.

To begin, I am extremely humbled that my mom chose to do this. She told me it is because I am "better at money" than she is, and I will know what to do. On the other hand, this raises some concerns for me. She told me that she would be placing her will in a safe and where the key and safe were located. 

I'm trying to help her come up with ways that she wants the money distributed... in words. In her head, she knows what she wants, but it is difficult for her to put it into words. I believe I know exactly what my mom would want, but I'd like to have my sisters know that I am just "following" mom's wishes.

Family Dynamics:
Dad: 43, on the verge of a heart-attack. Has yo-yo dieted his whole life and has lost/gained 100+ pounds more than 10 times, very money smart, very much a self-made "well off" guy.

Mom: 39, very healthy, very controlling, Spent most of her life as a SAHM, but is now an RN

Me: Oldest of three girls, 23, married, college education, own my own house, decent job, already almost out of debt.

Sister 1: 19, Not on good terms with the family due to her poor life choices, her dead-beat husband and father of her newborn, She is not mature for her age and squanders money when she gets it.

Sister 2: 14, will likely have much of college to pay for on her own or with earned scholarships/not need based.

I'm sure my mom wants something like, "Sister 1 can have "X" amount of money if "y". If not "Y", then she can have "x"amount of money when she reaches a certain age. How can I best help my mom write out this "will".

Can you succinctly summarize the text in 1-3 sentences?
<bot>: Mom is writing a will and I will have to implement it. How can we best write out the wording so that others receiving money will feel that I best acted on mom's wishes?