If my dad died, can the executor have the real estate attorney change the locks and is that legal?

He has the power to do it to prevent any unauthorized person from entering the house, but whether it was necessary is another question. The fees charged by the attorney hired by the executor are not regulated and can amount to a very high sum for very little meaningful work done. I would suggest you get all the heirs together and see what you can agree to as to dividing up the assets and then go to the executor to present your plan. That might save a lot of time and costs. Read up on the powers of an executor and how probate is handled by going to Nolo Press books that you should be able to find in your local library.