Well for some reason when I made a room and told my cousin CallMetin to join he did and I saw him then I logged out and went back in I went into the same exact room and didn't see him. I even asked if he was still in the room and he said yes and I dont see him in the room why?

Sometimes a room may "ghost" which means it disappears from the server list and cannot be rejoined (even through the /join command).

So do I have to make a different room with a different name?

Yes
Also, if you want to check if you ghosted or no just type /sa KenGee (/sa is a search command, if your name and room appears that means you didnt ghosted)

Gotta ask the question - are you both using the latest version of the game?