You have nothing to deduct. The money was never included in your taxable income in the first place, and you can't deduct something that was never included in your income in the first place.
To briefly expand, a cash inheritance is not taxable to the heir. Suppose the bank account was solely owned by your father. The money would have been inherited according to the Will, with each heir getting the specified amount or percentage, not being taxable. Instead, you were the sole heir, but you still paid no income tax. So the fact that you gave some money to a relative (it doesn't matter if the money was freely given or given under pressure) doesn't create a tax deduction for you, because you never paid tax on the money in the first place. It's just a gift (possibly) or a personal legal settlement (possibly), and neither is tax deductible. You inherited less, that's all.
I can't actually think of a situation where you could take a personal tax deduction for any expense associated with an estate. The estate should pay its own legal fees and costs, before distributing the residue. And even if there are legal proceedings that reduce your inheritance, that just means you get less free money and property.
I believe that the legal fees you incurred as executor can be deducted from the balance of the estate before the residue is distributed. You shouldn't pay those out of your personal bank account.
