My aunt had my grandpa's POA, she passed away. How do we go about getting changes?

blynnray, only your Grandfather can appoint someone new to be his Power of Attorney, and only if the lawyer you use feels that your Grandfather understands what he is signing.

Usually a second person is listed on a Power of Attorney in case the first person [such as your Aunt] is unable to act as your Grandfather's POA. I highly recommend that your Grandfather see an Elder Law Attorney so he will have all his ducks in a row.

nothing physically, but shortly after my grandmother died, he just started declining...he went to the grocery store and my cousin had to pick him up in Georgia because he got lost and confused

Hopefully the POA identified a successor for your aunt. If not, I don't know of any way to appoint another family member other than preparing a new DPOA. I'm not sure the existing one could be amended, as many documents can.

The question is whether your grandfather has any dementia or is able to execute a new DPOA. Has he had any such diagnosis?