Who is treated as a kind of deity (god) by the society?
There's two kinds of deities in Brave New World: Ford and John--just like there's two forms of God in the Bible: Yahweh in the Old Testament and Jesus in the New.
In the first half of the book, we have "Ford." He is a combination of Henry Ford and Sigmund Freud--as such, any iconic figure of that time who sought to control people by scientific or technological methods. He is also linked to the World Controller and the Director of the Hatcheries, as both men help proliferate the ideals of the utopia. Ford is very much like the God (Yahweh) of the Old Testament.
The deity in the second half of the novel is John. He is the Christ-figure found in the New Testament; the Son of God (Ford), or at least, the son of the DHC. He is the Chosen one come to free the people from their sins (or at least their soma). After he partakes in soma and orgy-porgy, he commits suicide, showing that the dystopia is beyond saving.
It is important to note that both gods fail: Ford & Freud and John. All are too connected to earthly things (materialism) to be spiritual deities. As it was said of communism: science and technology are the gods that fail.
If you are asking about who the society as a whole treats as a god, the answer is Henry Ford, the American industrialist who is given credit for really developing the assembly line system of production. (He founded the Ford auto company.) You can see this because dates are given as some year AF (After Ford) and people swear by his name. In addition, important people are called "Your Fordship" where English people might call a person with a title "Your Lordship."
The idea here is that Ford's assembly line brought mass production into the world and inspired the book's society where even people are mass produced. The assembly line also made possible all the consumer goods that are used to keep the people happy and the society stable.