it makes no sense why you wouldn't think something wasn't right after a while. though the picture of the fake girlfriend was pretty hot, so I can understand initially wanting to communicate, but after a while, it doesn't take a rocket scientist to realize something ain't right. these days if you can't physically be in the same place, you skype, especially 20 somethings.
I don't believe for a second he wasn't aware that it was fake. Maybe not at first, but it went on too long. Plus after she fake died, he said he used to spend 8 hours on the phone with her and how heartbroken he was. freakin' weird.