I am not familiar with GFI. I Think it is GFR that is Glomerular Filtration rate. This is most accurate test for kidney function. Its normal values in males are 97-137 and in females 88-128. Your husband might be suffering from kidney failure. His levels are further going down and he can suffer from acute kidney failure. These levels can also be less due to some other problems like Glomerulonephritis, congestive heart failure, shock, blood deficiency and chronic renal failure. If your husband is having kidney failure then you can not prevent it. If the problem is other than this then you can have some treatment. For more details, visit creatinine clearance rate.