Is Biopsy Advisable For Increased Renal Cortical Echogenicity?

Hello Doctor, My name is Srikanth. The question that i have is for my mother. She is diabetic for 28 years now & has undergone an Angioplasty surgery a decade back. She is on medication for her heart maintenance & for diabetes as well. On her routine check up, we found that her creatinine & urea in blood are high. Her creatinine level is 3 & the urea values are in the range of 70s. We have consulted a nephrologist & there was Abdomen scan (USG Abdomen) taken. The report reads that the organs are normal however, for Kidneys the report says, Increased Cortical echogenicity (Grade II) with maintained Cortico medullary differentiation . Also, they have suggested to do a Renal Biopsy since the scan seems to be normal. Kindly provide some direction as to if this Biopsy will be required considering my mother s medical history. Or will it cause any trouble to her system. I would also like to know what could possibly be the next course of treatment for her. Thanks in advance.