I am wondering what Tx law says about when an employer sends an employee out of town and wants to come back. He was told he has to buy his own ticket home. Is there a law protecting him from this unnecessary out of pocket expense?

Is there a contract... did the Employee quit before the contract ended..

If it's the Employees decision to return before the job is finished.. its the employees responsibility to pay his own way back. Particularly if the Employer paid to take them wherever they are.. and would bring them back after the job ends.