Dw, I have the EXACT same problem, I'll look for something for half an hour, ask my dad where it is, and it will be right in front of me TwT
This sounds upsetting, and I would first try to ask your brother to stop and explain how it makes you feel, and if he doesn't stop, just tell your parents. I had the same problem with a friend who would constantly "joke" and frequently call me a not very nice word, and I talked to them about it. They stopped but we aren't friends anymore lol.