My sister and I are listed in my dad's will that if the time comes, which it has that she and I are to have health care proxy and power of attorney. We have a note from the Dr stating that he cannot make decisions for himself any more due to dementia. We have given this letter to his attorney, is there anything else we should do?
Once you have the proper notarized copies of the POAs in hand; you can make additonal copies and have one on his medical file with his doctor/hospital, etc. along with your updated contact information. Same goes for the bank, investment accounts so that you have full access to father's accounts and investments and can make financial decisions on his behalf.
Going forward, whenever you sign anything on your fathers behalf you should use the wording "signed by Ms. Linda Doe, POA on behalf of father, John Doe". That way you aren't liable for any debts or other contracts outside the estate -- for example if you decide to contract for nursing care in the home; or residential agreement in memory care unit, etc.