Hi! Welcome to the forum! That's a long time of writing and knowing each other before meeting! If only the girl who I was in contact with had waited for more than just a few months!
Like Arthur says, would your friends family be able to sponsor you, seeing that it will only be for a couple of weeks, it shouldn't be too much of a problem for them. Also mentioning that you have met his sister should help a little I would have thought. Good luck!
