I'm afraid there is not much additional information here. There are only three cards in his record jacket. The first one shows him as the 3rd Corporal, Co. A, (Harris Guards), Arkansas Regiment. This regiment was also known as the 1st Regiment Arkansas Infantry- organized for state service. (The Colonel of this regiment was the great Irish-American Patrick R. Cleburne who later rose to the rank of Major General and was known as "The Stonewall of the West".) This card shows that he enlisted Apr. 30, 1861. The second card indicates that his name was on a muster roll for the company covering the period from July 23 to August 30, 1861. The date is significant because July 23 is the date that the regiment entered into Confederate service. This card states that he was enlisted July 23 at Pittman's Ferry by Captain Cameron. The period of enlistment was shown as 12 months from an original enlistment date of May 16, 1861. (No explanation of the discrepancy in dates of original enlistment - it could be that the older date was his original enlistment, and the later one being the date the unit was mustered into state service.) The War Department in Richmond changed the regimental designation to the 15th Regiment Arkansas Infantry on Dec. 31, 1861. (Because of this change, all of his cards are filed under the 15th Regiment - although all of his service was under the prior designation.) The third card shows him on a list of payments to discharged soldiers. It lists him as Corporal of Co. I, 1st Arkansas. It lists his date of discharge as Nov. 30, 1861, with a date of payment of Dec. 3, 1861. We can only speculate as to the reason for his early discharge. Poor health or severe injuries were probably the most common causes, but other reasons could have involved disciplinary issues.
To answer about short service periods: When he first enlisted it was very early in the war. It was commonly believed on both sides that the war would only last a very few months, and many early enlistments were for either 3 or 12 months. Later, in 1862, when the Confederate congress decided to enact compulsory service, many units simply reorganized and reenlisted for 3 years, or for the duration of the war. He was probably older than most enlistees when he first went in, but, if he had still been in service in 1862, he would have been joined by many more his own age and older.
As far as parents' names - you will rarely find that kind of information in service records. It was not something that anyone felt was needed information at the time of enlistment. About the only time you will find that sort of information in a service file is if a soldier died in service and a family member filed a claim for hispersonal effects and back pay. Usually this would be his widow. If not married, it would usually be his father. About the only time his mother would have filed would be if he had not been married, and his father was deceased. Even at that, many families never filed.
By the way, I imagine that you meant to post this on the main Civil War message board, as this board is specifically about Southern Unionists. Glad to help, all the same.