How did no one notice that before this? Did he not look under the car? I see a porta-power in the foreground there, word of advice, before you cut it out and replace, get it on a frame machine and pull the side out. Measure at the very least with a tram and get everything square. Strong chance the entire car is in a mild "C" shape. Even if you are replacing all the damage. Trust me on this. If not you'll cut out the damage, then when up you go to fit up the recycled stuff it won't fit. That damage extends farther than what you can see. If it's in a C the door will never fit right. Even if you don't think so, if you don't have any experience doing heavy collision repair then you need to get it on a machine, measure it and pull. Otherwise you just trade one form of butchery for another.
One more thing if you cut out the damage first then it is too late to pull it if you have to. You will be screwed. Get it on a machine, pull, and measure.