The Cement Garden (movie, 1993)

After the death of her husband, the mother of Julie, Jack, Sue and Tom begins to suffer from a mysterious illness. Aware that she is going to have to go into hospital she opens a bank account for the children, so that they can be financially self-sufficient and will be able to avoid being taken into care by the authorities. Unfortunately she also dies and Julie and Jack (the older, teenage children) decide to hide her body in the basement so that they can have free reign of their household. Soon Tom has taken to dressing as a girl whilst Sue has become increasingly reticent, confiding only to her diary, meanwhile Jack and Julie sense an attraction developing for each other. However Julie's new beau, Derek, threatens to unearth the many dark secrets within this family as he becomes increasingly suspicious of Jack.