He doesnt clean the bathroom!!

My bf and I are roommates with his brother. We have our own bathroom which has a sink and toilet that we obviously clean because it's ours. His brother has his own bathroom, the main bathroom that people use when there are guests over, that has a sink, toilet and shower area. I clean the shower because we all use it, so why not. But my bf's brother... oh god. He does not clean the bathroom countertops, the floors, the toilet (it is DISGUSTING), and barely takes out the trash in the bathroom and will pile it up and have all the trash overflow on the floor before he takes it out. Literally the bathroom makes me want to gag. There is random hair on the countertops and nastiness, and the toilet is like yellow/brown.. and the seat.. oh god the seat-- it has nasty small shit particles on it!!!!!!! I've only cleaned his toilet once (WHY???? DID I DO THAT UGH) when their mother was coming over and i knew his brother or my bf wouldn't touch the toilet. I didnt want her to come over and sit on a nasty toilet. She was like "wow matt (his brothers name), thanks for cleaning up the bathroom before i got here." And his brother said "yeah, no problem," and then my bf cut him off and told their mom that I was the one that cleaned it. Its sooo embarrassing because his brother's gf or girl friend or whatever she was would come over, and I hope she didn't think that we all use that bathroom!! My bf and I AND my toddler only use that bathroom for the shower because it is the only one in the house. It is just disgusting that he doesnt take care of it!! Im so glad that my bf, my toddler and i are moving out because I can't staaaand how nasty his brother is.