letters work great. i wrote one to my mom (i need to write one again) and left it next to her bed. it really helps when they don't listen. even trying to be calm doesn't work with my parents so a letter that they can read and think about and then talk to me works a lot better. good luck
(by the way, i would just leave it for them in a room you don't generally spend time in so you don't end up being there when they read it)