Negative income 1099 misc

Son is a full time college stud. We claim him as a depend. He has side job & received 1099misc for $12,389.00. Can he claim standard $12,000 deduct? Even so Turbotax is showing he still owes $1800.00. In addition he has mileage expenses that reduce his income to negative numbers but turbo tax STILL showing he owes $1800.00. Can this be correct?