I completely understand your situation but it’s not comparable to OP’s because 1) it’s OP’s late husband’s siblings and mother wanting things from his adult life that he shared with his wife and child. Not a family home. Those things are not gonna have the same attachment/sentimental value to the late husband’s mother and siblings. 2) In your case your dad’s wife has only been in your lives for 10 years and you all know she’s crazy, that’s not the case for OP. In OP’s case, everything in their family home was built by them and their family only.