Thanks NAC- really the most important thing he can do is get dialed in where he feels good and symptoms are addressed at the lowest possible amount of testosterone. That is why I commented about 200mg being kind of high. Generally you want to start lower and work up. When you start low, you help remove the possibilities of variables that could come into play- high E2, blood pressure, hematocrit, low/high free test, etc..
Once dialed in and consistent, then he will probably want to look at adding in pregnenolone and DHEA as they naturally lower with age and drop rapidly on exogenous test. It can really help with mood, energy, memory, and overall alpha feel.
HCG offers as benefits to TRT users primarily: helps with testicular atrophy, naturally helps keep pregnenolone levels elevated, and can help with fertility if one was to come off of TRT. However, I found that it dramatically increased e2 to the point that I spent so much time and effort controlling it that it was not worth it. I saw no benefits and only negatives, even on an AI. So rather than keeping all these adjuncts in, I removed HCG and then was able to control e2 levels and not need a regular AI.
I would recommend tongkat ali as an addition at some point as it works well to increase free test levels and that ultimately is what we want increased.