What is billy joel brother?

Billy Joel has a half-brother named Alexander Joel. Alexander is the son of Billy Joel's father, Howard Joel, and his second wife, Rosalind Nyman. Alexander is a classical conductor and pianist, based in Germany. He has worked with several renowned orchestras such as the London Philharmonic Orchestra, the Royal Philharmonic Orchestra, and the Munich Philharmonic Orchestra. Billy and Alexander reportedly had a strained relationship for many years, but have since reconciled.