My brother get rashes on body. Why he getting rashes? Please tell me sirs

Need more info. Too many types of rashes to help, see an MD/dermatologist to help. Bring with photos along with the who what when where of your brother's story. How long has he had it for, does it hurt, sting, itch, anything help or aggravate, any travel, any medications?
See doctor. There are many causes of rashes on the body. Your brother needs to see a doctor who will take a history and do an examination to see what the cause of the rash is.