God saved Lot why?

Gen 19:32says, “ Come, let us make our father drink wine, and we will lie with him, that we may preserve seed of our father.  19:33 And they made their father drink wine that night: and the firstborn went in, and lay with her father; and he perceived not when she lay down, nor when she arose.  19:34 And it came to pass on the morrow, that the firstborn said unto the younger, Behold, I lay yesternight with my father: let us make him drink wine this night also; and go thou in, and lie with him, that we may preserve seed of our father.  19:35 And they made their father drink wine that night also: and the younger arose, and lay with him; and he perceived not when she lay down, nor when she arose.  19:36 Thus were both the daughters of Lot with child by their father.”  OK, now I understand the daughters found some wine in a cave in the mountains and had sex with dad while he was drunk.  I am just asking how drunk could he have been.  These are the only two girls around.  Who did you think you were with?  If he was so drunk he was unconscious how could he have had sex with them?  And all importantly, what kind of upbringing made these sick sisters?  Who would let their kids read this?