Do you honestly think the Israelis would ever allow the Palestinians to take over or even have any influence over the Israeli government? They would never allow it. If Palestinians outbred them, they would simply mass deport them, or worse. No one would say anything because their diaspora control the only influential countries that pretend to give a shit about such things.

I haven't seen any country in [modern] history do what they say they would do. There wont be any mass deportations because none of the neighboring countries would ever agree to it (just look at the Syrian refugee crisis and how they barely struggle to keep up). If the situation got really desperate, than Israel would leave the land like they did with Gaza or the Sinai.

The Israelis would literally set loose nukes before allowing their regime to fall. They arent like white South Africans who voluntarily gave up their nukes and nation. Jews in Israel are a hundred times more ethnocentric than white South Africans were, and have far more power and influence because of their diaspora.

That's not how nukes work. If they launch them at another nation, they will instantly retaliate. So the only option left is again, to become like South Africa and absorb the bigger population.