Most Helpful Guy
First, as you mentioned, he doesn't know how to talk people. Internet is easier and more familiar way for him.
Second, he can message to you trough internet, he doesn't need to call you, or text you, because you already have a way to talk to each other. He is communicating with you, which is great, the platform doesn't matter.
Most Helpful Girl
Some people now don't even want to text they just use social media and it's obnoxious to me but maybe that's it. You can always ask if you think he's into you, it could initiate something more if that's what you want.