The fact that you got a 1099-S requires you to report the sale, not the 1099-S.
Use the correct amounts to report the inheritance and sale of the home.
When you mark it "Inheritance" it is treated as a Long Term Capital Gain or Loss, regardless of how long you held ownership.
Divide all amounts by four on your return if you are a one-fourth heir (unless the 1099-S already did this).
In description i would put something like "25% beneficiary of 123 Anystreet, Town, ST"
You would have to report this regardless of whether you got a 1099-S or not.
Once you figure it out you can show your siblings how to do it.
