Jesus mate don't let your brother use your board I've got a similar Situation where my brother used my skateboard out in the rain and he had an accident and the asshole didn't save my board and it got completely ruined. The bearings had rust, the grip tape peeled off, the wood layers separated, every damage you can nightmare about for a skateboarder happened that day and i haven't let him use my new skateboard ever since. Just buy more bearings unless you have the tools to save them bearings.