I would not recommend ordering a Soldier to sign a counseling statement. Soldiers have the opportunity to agree or disagree with the counseling on the form. If they chose not to sign the counseling statement you cannot force them to sign. You could have someone witness the Soldier refusing to sign and have the witness write a brief statement in the session closing block and initial it along with time and date. The problem is then solved in a professional manner with no need to get aggravated. You may also be interested in the following post: What regs states I cannot order a Soldier to sign a counseling statement?
Read The Mentor: Everything you need to know about leadership and counseling for more information about Counseling, Leadership, Corrective Training, and Separations in the Army.