Tim,
The first and most immediate step is to start communication with the student. Call, text, email, whatever will establish contact with the student. Then try to get a face to face with the student and explain that you are very concerned for the student and the developing pattern of skipping. Try to find out why the student is not attending class and see if you can find a mutual solution to the problem. This personal interest goes a long way in helping to get such a student back to attending class. If the reason(s) is so large that the student needs some time to get their life organized again, help them to step out of school in such a way that they know they are welcome to come back and start where they left off. I have done this with many students. Some came back and were ready to go, and of course others I never saw again, but at least I know I did everything I could to help that individual be successful and that gives me a measure of satisfaction.
Gary
Gary Meers, Ed.D.