I am expecting a large sum of money from my dads estate and owe the IRS

Without knowing the details of your situation--which you SHOULD NOT post online--it will be very difficult for you to obtain a useful answer in a forum like this.  I strongly advise you to seek the assistance of a tax attorney or certified public accountant regarding your taxes.  You should look for someone that has experience working with the IRS on offers to compromise tax liabilities.  You should also confer with an estate-planning attorney to see if there is a way to shelter the money from your creditors (including the IRS).  Bottom line:  Seek professional advice so that you can find out what your options are, and then follow through.  Good luck!