Who can deduct the loss will depend on the employment situation. Is she an employee or business owner? If personal vehicle used to commute to/from business location, then it's a personal property loss. If it's a business-owned vehicle, then the business claims personal property loses. All this also depends on insurance and situations of the loss (e.g., if you willfully negligent in causing the accident).
Losses arising from a car accident might be deductible from your federal taxable income. Deductible losses can include both property losses and medical expenses. A number of limitations apply to these tax deductions, however, and in some cases you might not be entitled to deduct any of your losses. You must file a separate tax return to report property-loss deductions.
You are entitled to deduct only as much as the insurance company doesn't cover, because this amount represents the true amount of your loss. Your loss might result from an insurance deductible, losses that exceed your policy limits, or undervaluation of your property by the insurance company -- your policy might not require your insurance company to take into account the antique value of your car, for example.
You may deduct medical expenses from your taxable income only to the extent that they exceed the specified 2018 percentage of your adjusted gross income.
You report property losses on Form 4684 and Schedule A of Form 1040, and you report medical expenses on Schedule A of Form 1040. Although you don't have to submit documentation with your tax return, you should keep records in case of an IRS audit. These records include the amount of your property loss or medical expenses, the amount of any reimbursement, the details of the accident (including the fact that it was not your fault), and your legal ownership of any damaged or destroyed property.
