How is the inheritance divided among a wife, one son, and two daughters, taking into consideration that the son built a bathroom valued at 400,000 rubles in his father's house, which is worth 2,000,000 rubles, and what is given to each heir if the son wishes to buy the house?

If the deceased left behind only a wife, a son, and two daughters, the wife receives one-eighth due to the presence of a lineal descendant. The remaining inheritance is for the son and the two daughters by ta'sib (residuary heirship), with the male receiving the equivalent of two females' shares. The estate is divided into thirty-two shares: the wife receives four shares, the son fourteen shares, and each daughter seven shares. As for the bathroom you built, its ruling depends on whether it was built during the father's lifetime or after his death, with the intention of donation or reclamation, and with or without the heirs' consent.