I am an only living child, my mom does not have a POA but I am named jointly on all her accounts, do I need anything else when she passes ?

I would check with the banks where her accounts are to see if you have right of survivorship. Most check ing accounts may be like that, but check to make sure

POA ends at death anyway. My cousin had this arrangement with her mom (my aunt) but it kind of backfired because she also had her name on all the credit cards and was stuck paying them all off!

A POA is about taking care of finances and business when a person is living but not taking care of it herself due to illness, dementia or just saying a want you to do it. You should be fine in this situation. If there is property she would still need a will unless you are on the deed.

You don't need POA if you're already on her accounts. I am POA for my mother-in-law so I pay all the bills etc. But when she dies, my legal job is cut off and only her sons who are on the account with her will have any rights. So you're good.