if he wishes to get the divorce by agreement, you will have to wait for her signature. He can however have someone serve her with the filed papers (Complaint and Summons) which tell her that she has a set time to respond, usually 20 or 30 days. If service of process is accomplished, and she does not appear, husband can apply to the court for entry of the divorce decree.
Unfortunately for your friend, it take two people to agree to a settlement. If the wife fails or refuses to sign the decree, due process requires that the wife be given notice and an opportunity to be heard before the court will sign a decree. To meet these requirements, your friend will have to have a summons issued, and hire the sheriff's office or a process server to deliver the papers to her. If she doesn't respond, he may have to file a motion for default judgment and mail her notice of that hearing. Though this may seem a burden, remember that due process protects your friend as well as his wife from abuse by the legal system. Remember that the rules exist to protect all of us, not just to inconvenience some of us.
If we do not have a written attorney-client agreement: I am not your lawyer; you are not my client; this is not legal advice.
Sign up to receive a 10-part series of useful information and legal advice about the divorce process.