My aunt moved in next to my grandparents some 30 years ago and has cared for them since that time. Then around 10 years ago, my grandfather died. Since that time, her assets have reduced by over $400k while receiving spouse military and civil service retirement and social security and payments for long-term care (over $7k in income per month). In the past 3 years, my grandmother has become more difficult and lost her mind. More recently, my mother is getting more and more upset that my aunt got financial and medical POA without informing her because my aunt pays her personal credit card bills, uses my grandmother's card as hers, eats out often/pays for other people's meals and generally seems irresponsible with money. So my mom, in an effort to prevent all the money from being wasted, cashed out a significant certificate of deposit and created a new account for it at a new bank. That way, if my grandmother (their mother) needs money, it will be there.
Un/fortunately, my mother also involved the state's elder financial abuse protection department whom made a determination that she was the elder abuser when my aunt recently gifted my grandmother's house to herself, in addition to two vehicles (a car and a van). And now there are also lawsuits, so now lawyers will get what scraps they were fighting over. Ugh. Stupid money family drama sucks.
Summary:
Don't put any adult children's names on any accounts. Bank accounts, investments, CDs, etc. should be payable upon death.
Do a will and living revocable trust. Probate and taxes can also take your kids' inheritance.
All adult children able to see but not use or modify credit card and banking accounts, and agree to financial decisions together.
Place a lock on elderly parent's credit reports.
Have parents split up/allocate inheritance before losing their mind/s or passing away.
Make wills specific so there are fewer arguments.
Have a single place (ie fireproof safe) where keys, documents, online passwords, bills, assets, properties are inventoried and include whom to call to cancel, transfer, etc.
Make end-of-life and upon death directives clear and precise.
If doing burial or cremation, get it pre-need because it's much cheaper and much nicer for the family.