Yes, he has to file.
Because he was paid on a 1099 he is considered "self-employed" and owes income tax and self-employment tax.
If he incurred any expenses as part of this job he can deduct those from his income to reduce the tax, but here really is no way to avoid it since a 1099-Misc was filed.
The IRS has an excellent resource for self-employed individuals.
Click Here: IRS
Self-employed Center