I was adopted as an adult , I was in foster care saw birth after several times he died no will and my siblings are to inherit why not me

I believe that Washington state law includes adopted individuals in its definition of heirs.  Most states do.   If your father died without a Will, his assets are distributed in accordance with the laws of intestacy in the state where he lived.  I recommend doing an internet search for "intestacy" in that state, as well as a search in that state for "probate definition of heirs".  Good luck.