My grandpa was diagnosed with septicemia. They are giving him antibiotics. What's gonna happen with him? What else we can do to prevent? Is it curable

Curable. Septicemia is a serious form of infection. With the right antibiotics he might very well be cured. There is always a chance that things might go wrong. Preventing it might be tricky. It depends on the source. He needs to have his vaccines up to date. If he is diabetic, his sugar needs good control.