I would suggest you to take a second opinion from a neurologist. Normally micro adenoma of the pituitary is not harmful for men, unless they keep increasing in size. Before doing T replacement, consult an endocrinologist and do a complete hormone evaluation, especially, Testosterone, estrogen, thyroid hormones and prolactin. Your doctor may ask for more testing. Decide on the course of treatment only after a compete diagnosis. By the way, what is your husband's age?
He is a very young 59-looks about 39. Otherwise very healthy.