There are many causes of blood in the urine.
Infection of the kidney or the urinary tract, prostate are the most common causes.
Stone in the urinary system may also cause blood with the urine.
Among other causes are clotting disorder, benign prostatic hyperplasia, or any growth of prostate, urinary system, hypertension, diabetes,strenuous exercise etc.
He needs to do investigation to find out the cause of blood in the urine.
I feel he should consult doctor as early as possible to find out the cause of bleeding.
I hope this information will be helpful.
Please ask if you need any clarification.