Creatinine level increased 2.85 to 5.09

Dear Doctor, My father is suffering from ckd from ckd from past 6 years and always maintain cretenine level from 1.7 to 2.35 and for the first time in July it's creatinine level is increased to 2.85 and now it's 5.09 . Size of kidney is normal. And other parameter is normal can there is any way to cure