What Is My Father's Wife Entitled To After His Death?

Location: Indiana. My father married his second wife and she moved into his house on his land. My father has 2 children, his wife has 3 children and they have no children together. All children were adults by the time they married. His parents and siblings have already passed and his 2 children are his only remaining true heirs. His wife is not on the titles to his house or properties. There was no prenup. He passed without a signed will. My sibling and I were supposed to get all of his estate and we would allow his wife to remain living in their house until her death. However, she will not sign the house and the land it's on over to us. Instead, she wants to divide their home and property between all 5 children when she passes. Can she do this legally? I've read conflicting information online. Thank you for taking the time to read this.

Edit: He had a typed document with his wishes (not a legal document). In it his wife was left money and other items but it said he wanted his house to go to us. I suspect there is no will because that's just not legal. I've never lived in IN so was just trying to find out what this will look like. I have no bad blood with his wife. She took care of him, kept a good home, was a wonderful grandmother to my children and treated them and us no different than her own children's families. Honestly, if it wasn't for her, my kids likely wouldn't have known him. He wasn't I've to take vacations but his wife made sure they came to visit at least annually. She's an old lady in her 70s and I would never think to evict her. I'm not a monster. I've done well for myself and don't need a hand out. This post was asking what legally she is entitled to. The answers here are all over the board so we'll find out once we meet with the lawyer. Thanks to everyone who took the time to read this and try to answer. Best wishes and, please, have a will in place for your family and ensure they have a copy of it. No will after a death is just a mess in the end, and we are all grieving as it is.