High Side P Channel MOSFET damaged after turn off
Ok, CC mode is almols like an inductor. You have to add a serious diode with anode on the GND and cathode on the output. The current then will flow through it without damaging the transistor. 

Upd: Oh, i known what is your problem. Remove the capacitor. And make the resistor between the gate and driver like 100r or even 0. You must close the transistor as quick as you can, otherwise the current times voltage is too high- power that heats it up exists for too long. Keep the diode, of course. In case your transistor's gate voltage is limited, make sue you get the maximum out of it. 

Upd: It's still gets burned, but now there is no power or overvoltage on the drain. There is still overvoltage on the gate. Change the resistors so they will be still much smaller than the initial 100k, and at the same time will not drive the gate beyond it's absolute maximum rating. Change R1 to 10k and R2 to 2k.