I am creating a POA for my 2 siblings and I

Hi,
my siblings and I are trying to create POA for my father to sell his apt that he shared with my mother before she passed in 2020. We are concerned about making sure it is all done properly and I am unable to find attorney in the States to help.
I have a document sent to us from India, however, there are multiple mistakes and I have retyped it.
My siblings and I live in 3 different states. Can we each notarize document separately, and then my father notarize and have 2 witnesses after we 3 have completed the notorization?
Does every page need to be signed only by my father (POA)?
Do we need attestation?