i had DPOA for both parents and registered the POA with their primary bank. i got an additional login for myself to their accounts, and if i wrote additional checks for them on their account I signed them as My Name, DPOA. the accounts were NOT listed as joint with me.

I later sold their house for them with the DPOA when they were committed to a nursing home.

brokerage accounts should have a Payable on Death designee set up.