His resume says he served as a 25B IT Specialist from only 2014-2016. Training requires 10 weeks of Basic training and then an additional 30 weeks of individual training. With a typical enlistment of a minimum of 4 years. So after all training doing his job for less than 1 1/2 years.
Information Technology Specialist Jobs (25B) | GoArmy.com
In that MOS (military job) it's unlikely he was medically discharged after less than a year and a half so he must have done something wrong and kicked out or found a way out of his enlistment.