hope4thebest,
Ralfinaz is our expert on that question. He recently (last month or so maybe) commented on this in response to another post. The side effects are due to the low testosterone, not the method of achieving it. The rest of his life is, hopefully, a long time. Things can change .. new therapies, etc. Having the "boys" removed is irreversible.
I strongly recommend a good exercise program (cardio and resistance training.) He needs to get regular bone density scans and perhaps be on some type of osteoporosis medicine to prevent bone density loss due to the lack of testosterone.