Why is our father so HURTFUL treating us all DIFFERENTLY and with favouritism?

Me and my 3 sisters are 34, 36 and 38 yrs of age. all 3 of us model, and the oldest girl is particularly successful and has made alot of money from it. Our parents are very wealthy so we've been lucky enough to be supported by them without any need to 'work any job just for the sake of it'. So we all could pick and choose what work we done and turned down. Anyhow, dad has decided that we need to move out of the family home although its like a 6 bed mansion on the edge of the city. He owns a few blocks in the city. He is giving one girl a penthouse, the next a two bed and i have to wait until after xmas for mine to be completed. Its also 10 mins walk from my sisters. I dont think this is really fair, as i'm the youngest, i ALWAYS have to wait for like everything. Same thing, i got my car for my 18th and it was 2yrs old, not a span new one. Why does dad treat us all differently and with obvious favouritsm. its very hurtful.