My sympathies. I wonder how well your siblings fare these days when the rest of the world doesn't go by mom's "rules."My older sisters would gang up on me. They would swap properties so that they could build houses and motels but they wouldn't swap with me. They only properties they would allow me to own so that I could build on were Old Kent Road and Whitechapel (the first two properties - I think they are Mediterranean and Baltic Avenue in the US version).
Playing with my younger brother was even worse. If he had to pay me a lot of rent he would run crying to my mother who would tell me he didn't have to pay all the rent because he was younger than me (Mum never said this when I was playing with my older sisters).