Employment Law Questions? Ask an Employment Lawyer.
What you can do is request the court if you can serve him by alternate service i.e. serve him at the company, leave a copy on his door, publish it in a newspaper. It is called motion for substitute service. This will usually be granted in this type of situation.
You can ask to have it posted on his door or other way the court will allow. The service by publication was just a suggestion but another method is to leave it attached to his front door or to leave it with someone in his home i.e. his wife or an adult child.
If my answer makes sense please "accept" and if you could a positive rating would be greatly appreciated. I wish you luck in your lawsuit.