I know this reply comes a full two weeks after your original post. First of all, know that any reading is based on the energies that exist at the moment of the reading. Second, energies can and do change. Because of this inevitable change, readings are probabilities...NOT absolutes. By virtue of knowing what the probability may be, you do have the ability to change the probable outcome. Third, practitioners must be very careful to read the energies as they exist and not project their own fears or prejudices into the reading. I strongly feel that this is what has happened in regard to your son and the military.
As a psychic with over 20 years of professional experience (I prefer to call myself a spiritual facilitator), there have been a number of occasions when my personal opinion was the exact opposite of what I was receiving. I did not let my personal opinion over-ride and presented the information exactly as it was coming through. Each time, the Universe was correct.
Your son is wise, even though it doesn't seem so many times. He is the type of person that has to experience things for himself. He will make the right decision. Remember, if you harp on the subject too much, he will do the exact opposite of what you wish just to prove he can. So, it is best to keep silent while letting him know you support whatever decision he makes. Ever since he was a small boy it seems he has gotten into scrapes (nothing malicious). It is because he is curious. He didn't have the maturity to think things through when he was younger (remember the paint?), but he is older now. Give him the opportunity to grow up. You will be proud of him.
As for the writing--by all means. Start with what you know. Don't try and determine what kind or genre makes the most money, write what you like. It is only when you are doing something that touches your soul that you succeed.
May you have many blessings.