There are a few things you can do. You can just sign the back of the title. (In some states that is enough for him to fill out the rest of the title.) Other states you will need a written bill of sale with the make, model, VIN, purchaser, date and mileage at the time of sale. Some states require notorization others don't. Do you trust your brother enough to give you the profit on the sale? Personally, I would protect myself and get a signed letter of whatever the car sells for is yours.
You can also have the title put soley in his name. Just go to your local DMV and have them transfer the title. For DMV purposes, you can gift the car and avoid taxes. Most states allow this. And when it is sold, he can sign the title. But again, how much do you trust your brother to give you the money? I would still get a letter saying he owes you for the amount of the sale. But that is up to you.
Transfering the title is about the easiest way to sell your car. Most states, you can get a title only without having to register it.
If you have to keep it in your name because of the plates and insurance, because some states will not do a title only, then signing a bill of sale and the title would be the way to go. But it is hard to give you a definate answer because different states have different rules and regulations. You may want to check with your local DMV and find out what the requirements and options are.How do you change the title to your car? or have someone else sell your car?
First of all is your brother at least 18 ? You can fill out a handwritten Bill Of Sale with a witness, and sign the pink slip. That should be good enough. However, I don't think your brother would do that, but handwrite a secondary promisory note that all proceeds go to you and he gets no money. Have him and a witness sign it. Then he can't come bitchin later that he was supposed to get some money or all of it..How do you change the title to your car? or have someone else sell your car?
Have your brother pretend he is you. Buyers dont ask for ID so no one will know.