I believe in the existence of a man like that, but I don't believe he was God's son or a deity in his own right. I don't believe anyone has the time to answer prayers, and I don't think anyone has come back to life in order to ascend. There are ways that a spirit can take a visible form, but I've never heard anyone address that properly, making me believe it to be a rare occurrence in our current day. I've only heard stories from Christians that make it sound like they're schizophrenic and passing as normal... like he's their imaginary friend.
In short, I think it is unusual to believe anyone could keep up with such a large group of followers, whether real or not.