If he's interested in "something", then he needs to do his research first. Like POB mentioned, if he doesn't include test as the baseline compound of a cycle, he's going to have issues other than his back. Every time you look to steroids for some specific effect, remember that you never get to pick & choose your results and sides. Very simply you are ****ing w/ your hormone profile because one of the effects is whatever you are looking for. But you get everything else that goes with it, so you need to know what you're doing. Have him read the stickies on the AAS board and do the research before even considering that route. Ignore whatever his buddies say about it - those guys tend to be the worst people to get advice from on a cycle. Do the research - the information and the experts are HERE. Otherwise enjoy the limpy dick and killed sex drive, followed by reduced test levels and early andropause, which of course will result in depression and general degeneration of everything.
RE: the spine - Oh for God's sake go see a doctor or a chiropractor and get an evaluation. Please see my thread on my strained AC joint. Shoulder problem? What does that have to do w/ your back you might ask? Well, after I got the MRI showing that my shoulder ligaments are basically overstretched, I got a set of x-rays. I'm 47 years old and have been living an extremely healthy life, I've been lifting since 1981 and I have a desk job. What did my x-rays show? My whole body is torqued to the left, meaning on opposing sides, left to right, front to back, one side is tight and the other is loose, so I torque. My rib cage & thoracic spine have very limited mobility (as I get older this can actually start to impact my vital organs as well). I also apparently have scoliosis and disk degeneration at bottom of my spine and my neck has 2 curves in it instead of one. Apparently the one minor car accident I've been in in my life, circa 1988, and the minor whiplash I experienced, has jacked my neck to the point that it curves the wrong way and there's continuing disc degeneration there as well. And btw, none of this is really due to all the years of heavy lifting and 10 years of competitive bodybuilding. It is from my basic structure and muscular push/pull balance.
When I was younger, I could muscle thru this stuff, but now it all is started to show. As you age, your growth hormone levels drop, and with it your ability to recover. So every imbalance becomes more pronounced. Over the course of 40+ years on the planet, this also means that where I have these imbalances, the smaller muscles are doing the work of the larger muscles that are no longer responding correctly since they've been working all these years to compensate for my fundamental structural imbalances and habits. This shit just continues to get worse as you age. I don't want to be all crippled up when I'm 60, so I'm working to fix it now. And the stuff I'm looking to do is not just go in for surgery. I'm literally relearning how to lift, sit, walk and focusing on retraining the parts of my body to not have to fight so hard to make stuff work.
In very simple terms, your body's primary directive is to keep your brain & your head upright. In the extreme, imagine someone w/ cerebral palsy - even w/ all the contorted joints, lack of muscle control, etc. the head is still upright. But the way the body has had to work to keep it upright is what ends up eventually causing the whole thing to deteriorate because everything is ending up having to compensate for other parts of the body, doing work they weren't designed to do. The end game is not pretty, and there's nothing that says the whole process can't be slowed down and even rectified by quantifying what is degenerating now, what causes it and what in the way you move / the way your body is / your habits that can be changed to keep it from progressing.
As mentioned above - AAS will help in things like recovery and probably mask pain via anti-inflammatory effect, but for a degenerating disc, that would probably just give a false sense of security and lead to much greater damange. It ain't "fixed". It might be something that would support a significant change in how he does things, strengthening of supporting structures, etc. But just running it w/o doing anything else would set the expectation that the drugs are goign to do all the work and that expectation can pretty much just **** you up. They are always only a support to foundational changes.