My grandma is in the hospital she has flu like symptoms and is severely confused not irinating much she had the IV reclast (zoledronic acid) yesterday. What's going on?

Delerium. Your grandmother is experiencing a common problem in elderly patients when hospitalized- the medical term for her confusion is "delerium" ; she has several risk factors: age, acute illness, dehydration, fever, unfamiliar environment (hospital) ; probably medications. It is unlikely the Reclast (zoledronic acid) is causing her confusion. Dementia also increases her risk- hopefully, she will improve on discharge.
Need more info. Reclast is also known as zoledronic acid, and is commonly use in hospitals for hypercalcemia (high calcium levels) and other ailments, such as osteoporosis. I'd look for at the kidney function and degree of hypercalcemia.
Only one . Who can answer is her physician (s) best way to find is , what's going on your grandma, if you are named in the health proxy , you can find and can help her, to get well and come home.