I've been reading and listening to a lot of information about closed head injuries. Some doctors are saying that even mild head trauma can cause hormone imbalances. Most the research has been focused on boxers and football players but a few have been looking at soldiers with PTSD. Anything from an IED to just firing a lot of rounds and getting bounced around in a vehicle can cause mild traumatic brain injury. Don't know what happened to your brother but if he is going the VA rout, getting meds and counseling, or tried the VA rout and gave up, he might want to look into it. Lots of people try testosterone and find it helps for a bit but doesn't last too long. The doctors who aren't just testosterone shot machines do a full hormone rundown and give all the precursor hormones and lower doses of testosterone (something like 50 different hormones are tested). Might be something too look into. I've heard some veterans who tried everything say it was the only thing that helped them.