First off so sorry to hear about your friend..
If your partner complains he is feeling weak, dizzy, faint or lite headed pull over ASAP.. Call 911, report your position, try to keep the person cool, give fluids if possible. Loosen restrictive clothing, apply a cool wet towel to neck and face if possible.. Do not allow person to lay down or sleep. If the person passes out and stops breathing you must start CPR. Lay the person down on his back.. No breathing, no pulse. Push down on the center of the chest hard at a rate of 100 times a minute, if possible. Use two hands criss crossed on top of each other to do this chest compression.. Now tilt the head back, check the mouth for obstructions. Remove it any way you can.. Now pinch the nose and cover the persons mouth with yours and blow hard twice.. Each breath should last at least one second, look for the chest to rise.. Then continue with 30 pumps and 2 breaths till help arrives.
God Bless
Duffy St.Pierre