Could zollinger-ellison syndrome cause death?

It can and it does. Ze patients eventually bleed to death from their eroded stomach linings, if they have not died first as a result of malnutrition from their damaged gut or the direct effects of their tumor. These folks also often have pituitary tumors and parathyroid disease, both life-threatening. Thankfully, ze is generally manageable. I admire your strength in asking -- be brave and beat this thing.