What can i do to contain my mentally insane fathers consitantantly opening of the bleeping back door?

he keps thinking that the aide is coming back here and opens the door ,either to get the heck out or for the aide to come here which isnt til 7am tomorow.he opens it and i shut it.this will go on until he gives up.i am fed up with this crap of his look i know hes sick and doesnt know where hes at,but im human and im waiting for a nervous breakdon to occur then it will be too bleeping late.he belongs in a home which my brother refuses to do and hes got his father terrorizing me with his alzhiemer fueled attitude.if he does not do something as simple as installing a door lock,ill be forever tourmented by my dad.its always after the aide leaves that he goes apebleep on me.NO SICK ANSWERS PLEASE.