Is It Right For My Brother In Law To Sleep On My Matrimonial Bed?

Please pals, your opinions are needed to guide me before I start creating unnecessary arguments with my husband's younger brother or his family. 

My husbands younger brother who just graduated from the higher institution is now living with us searching for a job .

But our house is just a seating room and a bedroom with toilet facility the type they call two room self contain in Lagos.
Sometimes I close from work on getting home I see him sleeping on my bed, sometime my husband will be in the seating room watching movies and his younger brother will be sleeping on our bed.
Is it right to allow him continue or to stop him considering the type of house we are living,? but at nigh the place he sleeps is the seating room while me and my husband sleep in our bedroom. Please your wise opinions will be appreciated.
Thanks