Odd Things Happening In Hangouts

I don't know if this problem is a Nexus 5, Kit Kat or Hangouts issue. I have been having an issue with sending my son text messages. If I go to Hangouts and enter his name or click his picture and send a text message, he doesn't receive it. If I go to him in contacts and click the text message icon beside his mobile number he does get the text message. If I go through Hangouts and click on the down arrow under his name it just says Hangouts. If I go through contacts and click the icon, it shows up in Hangouts with his mobile #. I have deleted him in contacts and re-entered all his data, but the problem persists. I have a feeling this may be happening with other hangouts, but this is the only one I'm sure of. Does anyone have any idea what is going on?