I have had depression and anxiety for as long as I remember but only began treatment for it at the age of 51, a couple years ago. My medications are Lexapro (a SSRI) and a low dosage of Abilify (an atypical anti-psychotic, sometimes prescribed to stabilize mood and to make the anti-depressant more effective that way). Both of these drugs have potential side effects that are minimal *for me* but that I had to consider when being prescribed.
My medications are helpful to me in maintaining my sobriety, but I was not put on them as a form of treatment for my substance abuse alone. I engage in therapy as well, with an addiction trained specialist, along with the medication and find that important to my recovery as well. I am not of the mindset, and I don't think it is a general medical conclusion, that such medication is alone a means for maintaining sobriety but for a depressed person, and one suffering anxiety, they can be a substantial aid. If he indeed has a dual diagnosis of addiction and mental health disorders like I do, it can take a trial of one or more medications to find what works, and these drugs take time to take effect. It's important to report any negative side effects that are persistent, and some medications require one be weaned off of them, not abruptly stopped, under the care of a psychiatrist.
Equally important to medication for me and for most is other recovery activity. That included the therapy I mentioned, learning cognitive techniques to help control my behaviors, attendance at AA for over a year as my primary support group, and learning to enjoy the things that sobriety gives, in my case. Each individual is unique in how s/he responds to treatment(s).