You need to know if the DHT lab ranges are age adjusted. The intent of HRT is to restore youthful levels of hormones. I do labs every six months, when I turned 60, suddenly my hormones were out of range! You should be able to argue for youthful levels.
And point out that there is no evidence that androgens cause prostate problems, only that cancers are androgen positive when they occur, and that modern research is showing that estrogens and estrogen dominance is the cause of BPH. And that low T causes estrogen dominance. Also low T reduces or stops sexual activity and lack of ejaculations leads to rancid semen and results in inflammation that then affects the prostate. Chronic inflammation is a well known cause of cancers.
The fact that prostate cancers can be treated with androgen deprivation and that this reduces bulk and PSA levels as the organ withers, does not in any why mean that androgens were the cause. You can also shrink a healthy prostate with androgen deprivation.
If DHT caused prostate cancers, then we would not see this as an old man’s disease. Men are afflicted when their T levels are low and they are estrogen dominant and also suffering from many other metabolic disorders of old age.
What I have not seen done, is to use 5-alpha reductase inhibitors to modulate DHT levels; instead of DHT–>zero. That would be an option, small doses. Some herbal prostate products might do this and many guys should be using these as a long term survival strategy.