Would taking more vitamins and fertility pills help if I have dead sperm?

NO WAY DUDE!! Find out what is killing the troops and fix it. Throwing vitamins and pills at dead sperm does not reverse the process that is killing them. Go to a male fertility expert and get figured out! dead sperm usually mean something serious is going on.
Yes. There are supplements than can improve sperm motility: l-carnitine, co-enzyme q10, folic acid, selenium, to name a few. If all sperm are dead, that requires a fertility evaluation as there may be something more going on. A normal semen analysis has a 50% non-motile sperm rate so some dead sperm is normal.