My parents decided that there were some things that my siblings were doing that were not acceptable in their home. They were afraid of their temper, but did mention ONE of the issues. I live with them and have POA and now they are ganging up on me and claiming that I am the one 'putting ideas into parent's brains.' Got a smear campaign going and basically trying to stress me out. Also wanting POA though parents named me many years ago. Suddenly they are very interested in financial matters....feel very bullied.
You say your parents are afraid of your siblings' temper. Are you, too? Are you on speaking terms with them still, or not really?
1RareFind is quite correct; there is nothing sinister in itself about your siblings' wanting reassurance that their parents' finances are in order. Getting everything down on paper in clear summary form *for your parents' use* would be a sensible thing to do anyway. And then if they wish to share that information with their children they are free to do so. Do you think that might make them back off a bit?