It is likely due to the
diabetes, I would advise you to meet a neurologist and rule out the cause and get the necessary treatment such as physiotherapy and necessary supplementation in improving the condition. I would advise you to check your mother's
sugar levels and if it's elevated to have it corrected so as to stop the progression of the disease. Diabetes uncontrolled can affect the nerves,
kidney, eyes, etc. so keep an eye for new symptoms and have it corrected at earliest