ADHD spouse's anger affecting child

My partner was diagnosed with ADHD before we met 14 years ago.  He takes Adderall 90 mg/day.  He is abusing the Adderall -- taking more than the prescribed dosage.  Two months ago, he admitted to running out 4 days before he could get his prescription filled.  He only admitted this after I asked him if he'd run out (it was apparent to me that something was wrong).  After that, we agreed that I would dole out the meds to him daily.  This worked for the first month.  A few days ago, I discovered that he got into the meds where I had hid them and is now going to be three days short this month.  I talked with him about discussing this with his psychiatrist.  He said he did not give me permission to do that, that he would not tell his prescriber, and if I did, he would just stop taking the meds.  He is an alcoholic, sober for over 15 years, and has gone back to AA at my urging.

In addition to and more troubling than the Adderall abuse is my partner's temper.  Fortunately, I guess, his anger is usually not directed at our 7-year-old son or myself.  Usually it is directed at the computer, his smartphone, or some other inanimate object that his frustrating him.  However, my son and I can't help but hear his loud and frequent rants.  The angry sounds and energy fill our apartment.  And often, they spill over into how he interacts with us.  He minimizes this behavior, calling it “muttering,” and says I am being oversensitive and controlling.  He gets angry if either our son or I communicate to him that he is scaring us.

To make matters more complex, we are homeschooling our son.  My partner, who is mostly retired, is the one who stays home with him.  Today, after my partner became very aggravated looking for library books that were overdue, my son told me he didn't want to go with his dad to his activities this afternoon, but didn't feel brave enough to tell him.  I told my partner and am now responsible for taking my son.  This is a joy, but cuts into my work time, which is stressful since I have my own business and am the primary breadwinner.  

My partner recently agreed to go to couples counseling, which we have tried twice before with very limited success. (I realize the fact that we are still together might suggest the couples counseling was quite successful, but we really worked out things ourselves, temporarily.)  I am in the process of looking for a therapist.  But my partner seems to be increasingly angry and I am becoming quite concerned about the effect this is having on our son.  I would be grateful for suggestions, as I am feeling very stuck and distressed.  Thank you.