Guy's Behavior

He texts me and goes offline within few seconds and then responds to my texts hours later?

He's always been a good friend in time of need. We text each other a lot. Few weeks ago he said he wanted to 'tell' me something but not in texts, he said he'd call in the evening.

Well.. He never called and has been avoiding my calls ever since.
Now he texts me out of the blue sometimes, a simple 'hi!' .. And goes offline within seconds.. And then hours later responds to my 'hi' with another.. I'm stuck in a loop of 'hi'
Help.. What does it mean?
He texts me and goes offline within few seconds and then responds to my texts hours later?
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