I don't think he is planning to do that unless if there is no other alternatives. Iran doesn't have what it takes to combat US and Israel so I think Iran should look for a more diplomatic way to sort things out with US because if US was actually planning to attack Iran . I don't think it will take then 24hrs to sink Iran to the marsh. However, Trump may launch attack if things get out control.
I think you are under-estimating the power and defense of Iran, actually. It is true their economy is almost destroyed and there is a very big opposition against the current regime, but that regime does not show any signal to be willing to get out the country and give up on power without a fight and bloodshed.
Also, it would not be very crazy to assume China will provide support to Iran, they are not likely to allow Iran to fall into the control of the United States so easily as it happened with my country: Venezuela.
I even suspect that Trump and his team of advisors underestimated Iran's military strength and capabilities. That is why they were caught off guard on the battlefield by strong resistance from Iran, and the war may last longer than they expected
Regarding China's support for Iran, that is no secret even if they do not openly admit it. Our world is currently divided into two extremes: on one side, the United States and its allies, and on the other, Russia and China. And Iran is a strategic and extremely important ally in their plan to rebalance global power. Therefore, Russia and China will certainly support Iran in various way
