USA Deducting balance due on 1040 as business expense

[Accounting101]

I have a client who owns and operates a business and he uses the schedule c for his business. For his 2013 tax return he owed the IRS $22,000 and he paid the balance due in 2014 and put it through the business as an expense, he says he can deduct it as a business expense. I told him he can not. Can someone please let me know who is correct in this situation. If I am wrong I would be the first to admit, but from reading all the possible resources Federal taxes paid is not deductible. He does have an EIN with the IRS but does not file as a 1120 or 1120S which I have told over and over he should. It would protect him if someone should every sue him among other things.

Can someone help me out.

Thank you
Lisa