Nations tend to get the kind of government they deserve, in God's providence. Until we acquire better character as a nation, we will not have better civil governments.
Your friend would be working with God as an agent of His scourge. As a man of integrity, he could still treat his victims with dignity.
A while back, I tried doing business as a Subchapter S corporation. The agency I found most helpful, and easiest to deal with was -- and I kid you not -- the I.R.S. The state unemployment gestapo, though, was so incompetent and heavy-handed that I disincorporated after a year rather than put up with their continuing harassment.
All I can tell you is that both of the two audits I went through ended up with me getting a check cut to me. The auditors were wonderful people.
I worked with a very good applications programmer way back when who used to be an IRS auditor - major anarcho-commie, Chomsky fan, you name it. He had some of the same reservations from a Lefty POV. (In fact he was so far left that people thought he was to the right of me. I was the only one at work who'd talk Marxism to him.) His take was almost Randian - it was that nothing in the job description really fell afoul of his standards and that taking money to do what was within them needed to be judged on its own merits. He said that when it came time to tear down the system he'd do it honestly. Interesting guy.