My brother and I have been playing for a few days now and even bought an expansion pack. We were having minimal issues with connection but now we cant even start a game together. When he tries to connect it also does weird things like changes his settings to newbie or normal speed while its set on my side to fast and normal difficulty. We were barely able to start a game together yesterday by exiting and joining the same game in a weird pattern but it switched the settings. today we cant even get that to work. Please help! only reason we got the game is to play something together while I'm very sick.

My first suggestion would be that your brother try to use the "Verify integrity of game files" option on Steam. If that doesn't help, we'll need his player.log and diagnostics files to try figure out what's wrong.