Yes, your husband is wrong, and I hope he'll reconsider what he plans to do. If he gets caught the penalties could be severe, but even if he doesn't, he still is failing to fulfill his obligations as a citizen.
But he isn't just wrong in the eyes of the law; he's also wrong in God's eyes. The Bible is clear: We have an obligation to pay our taxes, fully and completely. The Bible says, “Give everyone what you owe him: If you owe taxes, pay taxes; if revenue, then revenue; if respect, then respect; if honor, then honor” (Romans 13:7). Remember: The first Christians lived in the Roman Empire, which was far from perfect (and even persecuted them at times). But God still called them to be honest and good citizens, and so should we.
The real issue is this, however: What place does Jesus Christ have in your lives? Is He someone you think about once a week, or just when you get into trouble? Or is He the Lord and Ruler of your lives? Face this question honestly, and then put your lives — including your money — into His hands. The Bible says, “Examine yourselves to see whether you are in the faith; test yourselves” (2 Corinthians 13:5).
In addition, thank God for the resources He's given you; others in these hard economic times aren't as fortunate. The Bible says, “Each one should use whatever gift he has received to serve others” (1 Peter 4:10).