Here's the answer.  Tell him to consult with a tax professional

Your tax professional may tell you that when it comes to IIDs, commonly required for individuals with drunk driving convictions, in most cases for 2024 these expenses are not tax-deductible for personal use. The Internal Revenue Service (IRS) generally considers IIDs as personal expenses rather than deductible business expenses.

However, there can be exceptions. Be sure to ask your tax professional if you are an individual who demonstrates a legitimate business reason for requiring an IID, such as for a company vehicle or as part of employment conditions. If so, the expense may qualify as a deductible business expense. It's important to consult with a tax professional to ensure you are complying with IRS guidelines.

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