Going a bit deeper here, medications exist which block the receptors of testosterone itself rather than its production, but as a doctor will surely tell them sex hormones are required for healthy operation in the long term. If there is no estrogen being taken or produced and the Testosterone that is produced is being blocked then things like bone density become a very real concern over time.
If your friend won't visit with the Doctor I would implore them to at least consult with one on what the specific goals are medically and how they might be reached safely.