All his text does it try to draw you in to see if you're still 'talking' to him so he can keep you as a booty call
Agree with @HerLivingontheHill
OP, I had something similar in that a guy changed the way he texted me, but it was for the opposite reason. I didn’t sleep with him since he was unable to clarify our relationship and he was very annoyed. I feel his ego was probably bruised.
So he started sending very short texts and didn’t use my name whereas before he used to say “hey Batelyboo” then write a few well constructed sentences or even call me.
Shortly after he went completely silent and had the nerve to contact me 2 months later, probably checking if he still had any kind of access to me . “Just checking to see how you are” didn’t use my name and no mention of how he went of the radar for 2 months!
Of course , I ignored him completely at that point and ever since.
After I didn’t sleep with him I’d only maintained contact as I thought we might be friends of some sort.
However his behaviour in the weeks following that totally repulsed me and showed his character and true intentions regarding me so he is no friend of mine and doesn’t deserve a response.