re: is a power of attorney for aging parents a good idea?

It may be a good idea depending on who gets the named. The are horror stories of one of the children getting the POA from an aging parent and spending all the money and not on the parent.
My mother had split the POA where I had authority over her Brokerage account and my sister had authority over her bank accounts,
Have a will, repeat have a will.
Remember the POA expires at death, My sister was on the bank accounts(joint account) so we had access the bank account
My mother passed away at the end of January she had prepaid for her cremation so we knew what she wanted, She also had a will and we are in the middle of the succession now.
I suggest you and other siblings sit down with your Parent(s) and talk about your parents final wishes and where the money is, what insurance policies etc. These talks can be difficult but are even more difficult when time becomes a factor.
Good Luck