My Ex's Stepmother Is Taking It All.

TLDR: my ex-fiance's Stepmother is taking EVERYTHING now that his dad's passed away. But it gets worse.

Location: Florida, Jacksonville.

For reference, I'm 27F, married now to the love of my life. My ex-fiance is 26M, we broke up on good terms 4 years ago after a 5 year relationship. I was with him when his mom passed away, who he was very close to. But he was even closer to his dad. I'm talking visits daily. Working at the same company, aiming to be his dad's successor. They rode motorcycles together. Tightest father-son bond you'd ever see. I was close to both of his parents, not as much to his dad, but I still spent a LOT of time with him and knew him very well. He regularly recited his dying wishes: to be buried with his late wife's ashes, with her name on his headstone with his. Trusts were set aside for his grandchildren, and his assets were to be split evenly between his 3 kids. I'd witnessed him recite these wishes at least 3 dozen times while I knew him. Well, he passed away last weekend due to pancreatic cancer. His will was in place. Then, 3 days before he passed, he signed sole proprietorship to his wife of 4 years, giving her complete and total access to his assets, will, dying wishes, everything. She's selling all of the property and moving back to her first family's location to be with them, giving nothing to the kids or grandchildren, and terminated the trusts. She's not having his wife's ashes buried with him. She's TAKING HIS WIFE'S NAME OFF THE HEADSTONE ENTIRELY to be replaced with HERS. She has left his children completely out of any decisions. She hasn't even given my ex-fiance condolences for losing his dad, when he's the one that helped put him in a body bag. My ex insists that nothing can be done legally because his dad signed everything away with the proprietorship. But there are probably a dozen living witnesses who can say that she is NOT acting in his best interest, will, or final rights and desires. The will he had laid out prior to the proprietorship was accurate and up to date. Is there anything at all that can be done??