We come from a religious background where treatment is based on faith and home cures. What can we use to treat high calcium levels?

Reality. No religion forbids you to have a broken bone set. All the major world faiths accept scientific medicine as one of heaven's gifts to humankind. Not all hypercalcemia is serious, but if you have a parathyroid adenoma as the cause of your high calcium and you opt not to be treated, you'll feel worse and worse until it kills you. For the sake of the people who love you, do the right thing.
Proven vs unproven. By definition, "alternative" is different than modern western medicine. Generally any drug, herb, treatment, or procedure that stands up to rigorous scientific scrutiny is included in modern medicine. The problem is that many alternative practices, herbs etc do not stand up to scientific scrutiny and cannot be shown to work. They therefore remain "alternative". Soup may comfort but not cure.
Hydration. The treatment of high calcium levels depends on the cause of the abnormality. I do not know any faith based treatments that may be effective. In conventional medicine part of the treatment is thorough hydration, however, it may do damage if there is concurrent renal disease. I respect your faith, but would recommend seeking care from a physician in addition to your faith based treatments.
? For high calcium. No real remedies for high calcium, except you can avoid taking calcium containing food products such as milk etc. High calcium may also indicate serious underlying cancers. Needs to be checked out .