As recently as 2 weeks ago, text messages where working to and from this contact. His carrier with Tracfone is AT&T.
I've already done some troubleshooting:
Thank you for your reply. The phone model is: iPhone 6 64GB Space Gray (CDMA) Verizon Wireless MG632LL/A. The software version is: iOS 8.2 (12D508)
I will be sure to reply to this thread if it should become resolved at any point. If you have further troubleshooting suggestions, please let me know.
The model of the other person's phone is a Samsung, #SGH-T245G. While I've considered it may be on his end, it is strange that he is able to get text messages from others, and until about 2 weeks ago could get messages from me. It may or may not be related, but I'm fairly certain I upgraded to the iOS 8.2 sometime after the last successful message to him.