Microscopic hematuria can be due to urinary tract (bladder) infection, swelling in the filtering system of the kidneys, stone in bladder or in a kidney, blood disease, like sickle cell anemia, certain medicines and tumors in the urinary tract. Also the causes of low testosterone can be primary, secondary or tertiary and all the causes need to be ruled out.
Your husband may need a series of investigations like urine examination, urine culture, ultrasound or cystoscopy to confirm the diagnosis. Please consult a urologist and get it done.
I hope it helps. Take care and regards.