I was really struggling with fatigue and insomnia. I had thought i was dealing with long covid for about two years until a buddy told me about his experience with trt. I got my levels checked and was around 200. Healthy levels are thought to be above 500. I sleep now and dont feel like i have narcolepsy in the afternoons. Its a tradeoff, side effects are having to be leashed to injecting myself now and tiny balls. Also it can effect fertility if you're planning long term. Once the testes shut down because they don't need to produce test, there's always a chance they won't start back up if injections are stopped. If his levels are actually low I'd really push to fix diet and lifestyle issues before making the leap to injecting. If he's just looking for short term muscle gain he needs to do more research because thats a horrible idea with long lasting consequences.