My hair is completely dead, i cant style it, i dont even know what to do?

If it's really that dead than the best thing to do honestly is get it cut like a pixie cut, and then let it grow out. You need to stop styling it, let it air dry with defrizzing and wave enhancing sprays, use a deep conditioning and hot oil treatment once a week, get trims often, never style your hair with heat if it is wet. If you go in the sun a lot put sunscreen on your scalp (I know it sounds weird) and if you go in chlorine or salt water a lot always wet your hair before going in and put a leave in conditioner in it to protect it.