My son has a small construction business under 1 million and he has no cost of goods sold, the main contractor provides all of the material for him so all he does is bid the job and pay 1099 to his employees and pays for expenses such as small items that he needs in addition to his job, would that be considered just all expenses. There is no inventory.

Many service businesses have NO inventory.

His expenses are the wages he pays his employees and the small items needed to complete the job, which would be listed under "Supplies".

Any competent tax preparer can prepare his return.