You gotta consolidate your bench threads, man. Relax, lol.
He should do his normal warmups. There is plenty of info about warming up. He should get up to around that weight in increments. You really can't conserve any energy in an actual competition due to the pause at the bottom of the movement. They tell you when you can move the weight again. There's very little/no storage of elastic energy due to this. Therefore, he will be able to lift less weight with powerlifting form than with normal gym form.
EDIT: Also, man, you gotta try to research this stuff before you ask here. Asking every question that pops into your head makes you less self-sufficient. You can find the same info by googling and that saves everybody a whole lot of energy. It's a suggestion - take it or leave it.