My dad has Alzheimer's and a will in place for his property. One brother has power of attorney and the other brother wants to put my dads house in his name. There is a very specific will in place, was put in place before the diagnosis regarding the house.
I am pretty sure that the brother without POA can do nothing at all.
The brother with POA might be able to make changes to the deed but it depends on the wording of the POA.
A POA is supposed to act in accordance of the person's wishes or in their best interests. If a POA is not, then you could possibly go to court and try to get guardianship.
Should your Dad pass, the Will will need to go to County Probate. The Probate Court will question why the house title is in your brother's name while the Will says something else regarding the house.
Another thing, if your Dad ever needs to have Medicaid pay for his care, Medicaid would place a lien on the house. It could be that all the equity would go to Medicaid depending on how long your Dad needs this program. That brother would need to either refinance the house, or sell it.
Another issue, parents shouldn't change the Deed to remove their name and add their children's names. That changes the capital gains taxes to a much higher amount. The bases would be the amount that the parent had paid for the house when the parent had bought it.