What Causes Severe Fatigue And Sleep Apnea After Undergoing Testosterone Therapy?

my husband who is 71 is extremely tiered all the time. He has been on testrone therapy about 1 1/2 years. If he gets still he falls asleep. He suffers from sleep apena also. His coloring is white and it seems he has aged right before my eyes. Where do I seek medical attention? From an internist, heart or etc.