Ann, My great-great grandfather Robert Maxwell had and older brother John.  He was born in Ulster, Irleand.  He and his parents immigrated to PA in 1830.  They settled near Stewart's Station, Westmoreland County.  If this is the John you are looking for the only info I have is that he died from wounds recieved at the battle of Sulpher Springs, during the Civil War.  I hope this info helps you.  Becky Maxwell