Why does he behave like this?

pick his brain more to get all the details. maybe your guy wants to read on the internet (which many people do) and doesnt feel like chatting. its common that these im' things people second guess or ume something bad or that is somehow an affront to those contacts on their list if they dont spend all their time chatting with everyone. chill out. if your guy is appearing offline when he's actually online...well, how do you know that anyway? ? cuz i'd like to know that too. hehe