Boarding school in Madrid /Host families

Hi everyone, we are moving back to the U.S from China and my son has been invited to play soccer at a major club in Madrid during the academic year Protected content . He will start high school this September and we are looking for a boarding school for him. We were told both British school of Madrid and SEK El Castillo have boarding facilities. Anyone familiar with the schools? We would prefer the American School since we are from the U.S but they don't have boarding facilities. Does anyone know if there are options with host families for a full academic year? Thanks in advance for any referral! Cris