Hi, welcome to health care magic, i am sorry that your brother is feeling unwell
is a chemical that is produced from the muscle,it is transported through the blood to the kidneys.
The normal values are 0.5 to 1.2 mg/dl which is 44 to 106 in other units. Different labs may have varying normal value ranges. The value of 130 is slightly above the upper limit.
Elevated creatinine is usually associated with kidney disease. Other causes are excess intake of meat, as a consequence of some medications.
Your brother's doctor may consider screening him for kidney disease which may involve futher blood tests, urine analysis. Imaging may also be considered.
i hope this information is helpful