There are lots of different options, and one that is wonderful for certain situations may be poison for others. That's what a good estate attorney can advise you on, AS YOU ARE PLANNING. I'm in my 60s, and having watched a lot of family and friends over the decades, I'm convinced that there are 2 types. There are the people who could drop dead at 40, and their estate will be perfectly organized, and there are the ones who refuse to discuss it, with terminal cancer at 90. If your parents won't planning for deathin their 50s, they aren't going to suddenly start considering it in their 80s. The more likely it is, the less they want to believe it's real.

We put a condition in our will if you contest anything you will get nothing. I don’t want what we saved and invested going to attorneys. All of our accounts have beneficiaries listed so it should be easy.
I could be wrong but a POA is useless after death.
We learned some things the hard way after my mom passed.

I recently purchased a Revocable living Trust, wasn't cheap but worth it in my opinion

A conservatorship is a form of “Power of Attorney” but it’s just for assets and finances.

Yes a POA expires at the death of the individual, the will then becomes the dictating document.

if you can get everything in your name or whoever will benefit from estate. There is a time period of ( I think) 2/3 years that this has to be done before death of original owner. Plus make SURE that there is a will. Had this happen with my Mom that causes all kinds of problems if not done correctly