Business & farm

If his father inherited the truck, the cost basis would be the fair market value of the truck when he took possession of it, so it is doubtful he would have a taxable gain of the sale of the vehicle. If the deceased had title to it, it would belong to his estate that would be created by default when he died. If the sale proceeds were more than the cost of the vehicle less depreciation then the estate would report income on the gain on an estate tax return. The estate tax return would only be required if the income of the estate was more than $600 during the year.

The jeep was not sold until after the business was ended so its sale would not factor into the final return of the deceased as far as the business is concerned. You indicated that in TurboTax you said you stopped using the vehicle so that was correct.  You should also indicate that the vehicle was put to personal use on the screen that says Do any of these apply to the (name of vehicle):

If your son had taken an expense deduction for the vehicle, such as section 179 or bonus depreciation, you will need to account for that as depreciation recapture in the Less Common Business Situations section of TurboTax. You would have to look on page two of the depreciation schedule Form 4562 from a previous year to see if any section 179 depreciation has been taken. It would appear in column (i). If bonus depreciation had been taken, you would have to look on line 14 of Form 4562 in the year that your son put it into service to see what that amount of bonus depreciation was.

If you need to recapture depreciation because of bonus or section 179 depreciation, you will see instructions on how to do that on the screen that says Conversion to nonbusiness use:

So sorry for your loss!