WHAT SHOULD I DO???

I am my father’s only child. He told me before he died that he had a will my step brother was the executor. When dad died, my stepmother suddenly became the executor. My dad inherited family property from my grandfather 1968. After dad died total silence and no communication from my stepmother. I asked to see the wheel for five months and she refused to let me see it only when I threatened her with court did she send me a copy and I believe it was edited. Nothing that dad and I discussed was in it. She wants to sell the property and keep all the money. She has already sold his pick up which was in his name only., and refuses to file with probate. Dad‘s been dead six months. She says that her and dad have joint tenancy on my dad’s inherited property, But none of the deeds that I have looked at in the Southern registry show that. I smell a rat... What can I do???