Gift Deed and Property Transfer of Deceased

I have recently discovered that my Mother passed away. We had a rocky relationship due to her Alcoholism. in 2017 my father passed away intestate, My father was a musician as am I. He had guitars that are very dear to my heart and are worth an substantial amount of money. I would never sell them. anyway, my mother claimed all of this property as community property. She used an Affidavit of Heirship to remove my fathers name off the deed of the house and Gifted it to her cousin which is also named her Executer over her estate. My mother did have a will and left me a dollar supposedly. My question is the Affidavit was used 3 days after it was filed to transfer my fathers name off the deed. I plan on going to court and filing an dependent administration form to at lease have my fathers half of his property. After extensive research I have found that an affidavit of heirship has to be filed 4-5 years before it can be legally used in court as evidence to transfer property. If this is the case I would like to know if I can get this reversed because of the fraud committed. I was also not notified when the affidavit was filed because my mother did all this behind my back. this would make it fraudulent as well?