The revolts in the Philippines had been suppressed, the islands were peaceful now, and in the wake of the Washington Naval Treaty, the garrison was being reduced. MacArthur's friendships with Filipinos like Manuel Quezon offended some people. "The old idea of colonial exploitation", he later conceded, "still had its vigorous supporters." In February and March 1923 MacArthur returned to Washington to see his mother, who was ill from a heart ailment. She recovered, but it was the last time he saw his brother Arthur, who died suddenly from appendicitis in December 1923. In June 1923, MacArthur assumed command of the 23rd Infantry Brigade of the Philippine Division. On 7 July 1924, he was informed that a mutiny had broken out amongst the Philippine Scouts over grievances concerning pay and allowances. Over 200 were arrested and there were fears of an insurrection. MacArthur was able to calm the situation, but his subsequent efforts to improve the salaries of Filipino troops were frustrated by financial stringency and racial prejudice. On 17 January 1925, at the age of 44, he was promoted, becoming the Army's youngest major general.