Need for Speed Carbon: Own the City

Ok, first what race did he beat and make sure u don't have cheat codes activated

Well I don't know how your brother did this,but I do know another glitch in this game.The glitch let's you take any car you want without spending a single penny!( You can only select cars you have unlocked.The locked cars cannot be used.)First,come in the MAIN MENU of the game.Then select QUICK PLAY and then select SINGLE RACE.Then when you are select the car,then select STOCK CARS.Then select the car you would want in the career mode.Then when the race begins,you don't need to play it,just select QUIT in the pause menu and you will come back to the main menu.Then select MY NFS and then game data.In that select SAVE and select your profile.Then choose load and load your profile again.(You have to do this save load procedure even if you have autosave turned on.)Then go to OWN THE CITY option and then select continue and there you will be having the same car you had selected in the single race.
Note:Your old bought car will be there in choose car option.Under your old car it will be written owned.But if you buy any other car select any of your owned car,your new car will go away and you will have to buy it to use or use the glitch again.Also,if you are having the new car,you cannot have another with it using the glitch.
Hope you enjoy using cars for free!