Priscilla Presley has a "good chance" of victory in her battle over Lisa Marie Presley's will

Benny Roshan, a probate, trusts and estates litigation attorney based in L.A, told PEOPLE: "The law basically says follow whatever is in the document, and then the document says this is what you have to do, So if the court is looking at it and truly those procedures were not followed, Priscilla has a good case of arguing that this new document that essentially replaces her is not valid. That's a good point if it was never followed. Cases like this depend on whether or not other interested parties and family members disagree with Priscilla's position. If no one objects it can be completed in as little as a few months,

"If someone objects to her position and takes a contrary position, e.g. that the 2016 amendment is valid, the litigation can drag out for years. "

Priscilla - who married late music legend Elvis in 1967 but split from in four years before his 1977 death and went on to have Navarone, 35, with entrepreneur Marco Garibaldi - recently explained that she is going to court over 2016 in the amendment because her only "wish" is to keep her family together.

She said: "Today would have been Lisa's 55th birthday. My wish is to protect my three grandchildren and keep our family together. From the first moment I held Lisa in my arms, I've protected, loved and guided her, as I have my son. Our hearts are broken, and I am having to learn to live without my only daughter."