mother will not hand out late dads possessions

My father passed away without a will almost ten years ago. The problem I have is that my mom says that though he had no will because she is his spouse all belongings automatically go to her. I read in an article that actually according to state of texas law, 1/3 goes to her, 1/3 to my brother and 1/3 to me. Nothing is of dollar value, sentimental and heartfelt. She refuses to let anything go. What are my rights??