Unfortunately, there is nothing you can do to force him to file a tax return.
The IRS and the states both do require that you file a return, once your income exceeds a certain limit. The limit for 2008 was $8,950 for a single person and $17,900 for a married couple. If earnings were under that amount, then a return does not need to be filed.
If he had earnings over the limit, then the IRS may contact him, but only if it appears that he owes more tax than what he paid in through his payroll deductions
. The IRS and the state has copies of his W-2 forms which will show the income he received and will also show the tax he paid in for the year. If he had enough taxes withheld to cover what he owes on his earnings, then the IRS may not even contact him to file a return. If it appears that he did not have enough tax withheld, then they would send him a notice of his tax deficiency, which would then force him to file a return. However,if he ends up owing tax, then obviously that will not be of any benefit to you, as there would be no refund to offset for the child support.
If he waits more than 3 years to file a tax return, any refund to which he may have been entitled would be forfeited and would be of benefit to no one.
There is one thing that you can try, although there is still no guarantee that the IRS would contact him to file. But you can fill out Form 3949A and send it to the IRS. The form is an information referral to report taxpayers who are not following regulations. One of the things you can report is failiure to file a return. This may at least get the IRS attention, and hopefully they would contact him to file.
I realize it may be hard to reason with him on this, but he should understand that if he has a refund coming, then at least by filing and having the refund go towards the support he owes, this would reduce his overall liability to you. It does not make good sense for the refund to benefit no one, and perhaps even be lost entirely if he waits too long to file.
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