why in the TO box my contact is blue and say chat instead of text message

[Android Central Question]

when using my android to text all my contacts are orange in the to box and it says text message under details. but my X is always blue his name and under details it says chat.. except his co-workers name comes up orange and say chat also.. does he have me in a group chat or something.. because i will get responds from him and i swear there not him