he must keep records of the business mileage driven. regardless of whether the standard mileage rate is used 57.5/ business mile or he uses actual expenses.    

If you want to use the standard mileage rate to calculate vehicle expenses, you must choose it in the first year you use the vehicle for business. In later years you can choose to use the standard mileage rate or switch to actual expenses.

Once you use actual expenses for the vehicle (even if it's the first year you used it for business), you can't switch to the standard mileage rate. You must continue using actual expenses as long as you use that vehicle for business.

If you use actual expenses, you must have records of all expenses and must allocate those between business and personal use.

the standard mileage rate includes an amount for depreciation of the vehicle.  so if you use this method you can't depreciate it.  should the vehicle be sold or traded in you must compare the sales price to the depreciated value (cost less the business miles for each year times the standard mileage depreciation rate for each year) to determine taxable gain or loss.