It does look like there may be some kind of problem with the connection to Seattle there. How close to the server are you, and how close is he? It may be just a problem between you and him that doesn't happen when he connects to the server, or when you connect to the server. This isn't too uncommon.

The latency between you and the server is a big deal. The latency between two clients isn't really important, unless those two clients talk to each other directly - not too likely unless you or he is hosting the server directly.

Best wishes,
Pete