The first thought that comes to my mind is that he may be experiencing stress-related anxiety which can produce many different symptoms and if it is stress, there needs to be some lifestyle changes. You indicated he's employed, married and has a young child--all things that can produce a stress build-up.
Most people don't understand that stress sneaks up on you. You think you're doing well and handlng things just fine and all the while the stress is building. When it reaches a point where it can't be handled any longer, symptoms break through and they are usually in the form of severe anxiety, physical symptoms and a sense of hopelessness. There is hope but a plan of action must be designed for him.
My next thought is that he needs an evaluation with a psychologist so that he can get an accurate diagnosis and treatment recommendations. There may be a need for marital counseling (to help them both manage his stress or the stress in the home or on the job). All of these are positive steps to improving how he feels and getting back to be in control of his life again.
Every state has a psychologist's association and you can find all of them with an internet search. The association can provide the names of 3 psychologists in your son's area or nearby (hopefully) and then he can do a phone interview to see which one might be most helpful for him. Please go to my website's Therapy page (www.drfarrell.net) and read what needs to be discussed in this initial phone interview. Remember, he may need some help with this and his wife or the two of you might need to assist in some way. Be prepared for this.
Self-help in the form of lifestyle changes is also helpful. So, he needs to have a balanced diet, some sort of exercise routine (now becoming standard in treatment plans), sufficient sleep (very important) and some time for recreation. If these things are dismissed and are not part of his life, he may have a less successful attempt at a return to a more pleasant, anxiety-limited life.
Anxiety is a part of life, but as I said, when stress builds up, it blows everything out of proportion and begins to affect the way someone views everything in their life.
I hope you find this helpful and I do hope that he gets the help he needs.