Attack of the End of Stream Team

[H477150n]

My friend hosts the server. I've been playing on it for two months with my wife at our house. We use a wifi connection. About a week ago, both of our connections to the game are whacking out. We first try to poll the server, the game then tells us "can't reach server" with a big fat X on the connection bars. We double click/try to connect to the server anyway and we are able to connect. Within a minute, however, we are disconnected with this " Connection Lost -next line- Internal exception: java.net.SocketTimeoutException: Read timed out". Also, during that minute of playtime, we are able to interact with items for a few seconds before it lags out and we can no longer interact with items. At random times, when polling the server, we will be able to see it up and running again, and of course we cheer thinking it is fixed and we will try to connect and get a "Connection Lost -next line- End of stream"

We have tried communicating with our ISP, they did whatever to our router. We turned it off for a few minutes, ect. We have tried flushing the dns in the command prompt with the ipconfig/flushdns command (can't recall exactly what the command was). We have had my friend delete our player.dat file. 

Oh and here's the kicker - our other friends (non-hosters) are able to login to the server and play without any issues, so it is not the port forwarding issue.

What can we do next?