Can we discipline for bad behavior at party?

Q. At our company holiday party, which was not at the workplace or during work hours, an employee told some inappropriate jokes and put an arm around a co-worker who did not appreciate it and complained. The company is aware that the employee took a leave of absence for treatment of chemical dependency and is concerned that the employee might have been drinking at the party. Can the company discipline the employee? The company would like the employee to get additional help for chemical dependency.