How do I remedy this problem?

I had given my garage on Rent to my next door neighbour and I am parking my car in my sister place from 08/10/08 Now what ever Rent I get , I share 50% with my sister. But the problem is that my sister gave her garage to my other brother for free parking, where she is paying maintaineance charges for garage and flat, but now my brother is objecting for giving garage on rent because he has to park the car, outside, what to do ?   I have Maruti 800, My brother has accent  my neighbour has BMW and my sister is staying abroad,  Please give us good solution to this problem, because if i park the car outside , i will loose image because my borther is not staying my bldg , he is staying in other building opp to me.