That's like my family! I have 3 younger brothers - the oldest one is called "abang" (elder brother in Malay), the middle one "adik" (younger sibling in Malay) and the last one by his name, or just "the small one." The one we call "adik" is now taller and bigger than both his older siblings, so people always think we're bullshitting them. It would be quite funny if the small one grew up to be even bigger.