I would tell him, that if he wants to do this, he has to do it out of your house. He can have his own fetishes and keep them to himself and or/with people that dont mind or like it. There isnt any reason that you should have to deal with it in YOUR home if it makes you uncomfortable. Im surprised the rest of your family is so tolerant. If my brother did that I wouldnt even know what to think. I dont think somethings wrong with him, but i dont think your 'wrong' either. If you dont want the furniture in your house tell him to get it out or throw it away.