Most nephrologists swear by Farxiga. If your brother looks at the side effects, he may be in that group. I followed my trend before Farxiga and after the 2 times that I had taken it. I should have learned my lesson the first time, but the second time got me back again into Stage 4, and I knew I had to stop that medication. It took me nearly 3 months to get back to Stage 3A.