To comment on the OT bit, Alot could have to do with the dietary laws the Jews were/are under. By that I mean, the Jewish laws when it comes to food, and hygiene is relatively rigid, and unlike any other in that time, but from a scientific viewpoint they are spot on(perfectly illustrated when the Plague hit in medieval Europe). That means that if they would not have killed all men, women, even children, and animals, they would have been at risk of all kinds of diseases. Now I don't know why all the babies were murdered in Egypt, but I want to stress this, Moses his upbringing was VITAL in who he became, and the rol he had. He was groomed for the liberation of the Jews for many many years, so that might have had something to do with it. Also do not forget Satan has always, and still wants to destroy the Jews.
The bible condemns any sexual act outside of marriage so your friend fails there misserably. Sodom and Gomorrah were rotten to the core, and God knew their heart alot better then we can even begin to estimate, and He saved Lot for his heart was eager to serve Him, He clearly saw hope in the hearts of Nineveh.
Your friend speaks of that we need a smiting, and that it's weird that we haven't had any for a long time. Well scripture clearly teaches that we are living in the age of grace, so that makes sense, but at the rate we are going now, there is going to be some smiting going on soon. Also you could ofcourse point at him for example how the British empire fell, shortly after turning their backs on the Jews yet again.
There is nothing telepathic about talking to God.
Now on that he speaks on other religions, how do WE know we are correct and how are those that are wrong judged? Well those that are wrong are judged on the Light they received, afterall you can't be condemned for something you did not know was wrong. How do we know we are right? Well you could point out numerous of things, fulfilled prophecies to name one, or things like the perfect dimensions of Noah's Arch. Also you could point at the obvious flaws of other books, like the 6creation stories of the Qu'ran. Anyway, it aint perfect this response, but hope it helps.
