If no appraisal was done at that time, you will need to engage the help of a real estate professional to provide the FMV for you.
Your total shared basis would be the inherited basis plus the cost of repairs & improvements.
Each owner would report an allocated portion of the sale transaction on his/her individual tax return. The buyer’s concession would be deducted from the gross sales price, either as an adjustment to gross proceeds, or as a selling expense.
For additional information regarding this, please refer to: IRS: Inherited Property
