level shifting 5V pulse to 12V pulse
The most apparent serious problem with the circuit is that you have the Source and Drain of this FET wrong way around in the circuit. Note how the body diode will conduct a lot of current when the lower FET tries to pull low.



If you want a chance of getting a 5V to 12V driver circuit working prepare it more like this configuration and get rid of a couple of transistors in the process.