Portland philanthropist Arlene Schnitzer has died at the age of 91. Her son, Jordan, told Business Journal news partner KGW.com that his mother had existing health issues and passed away of old age. Schnitzer, her son, and her husband, Harold, have supported countless organizations. Harold died in 2011. In 1994 the couple co-founded the Harold and Arlene Schnitzer CARE Foundation, which has funneled financial support to dozens of local organizations, including the Patricia Reser Center of the…