You have a repo on your credit because you let your brother take over payment on this car and he never paid you was not awhere and the car was crashed and sold for scrap how can you fix your credit?

You can't. If you alllowed your brother to take possession of the vehicle without refinancing it in his name, you are the one who's credit is damaged. Also the lender will hold you responsible for any money still owed. The entry on your credit report will remain until the required time limit expires, which is usually seven years. However, any further legal action on the part of the lender or another collector will create further damage to your credit history.