AutumnMama.....the way I look at it....I believe that she deserves to have all of the cards on the table...if she is drug into the middle of this, anyway and extending herself to help out. I think that it is fair to you for her to know the facts of the situation....otherwise, you could be made to be the "bad guy"......and he needs to be honest with his mother if he is taking help from her....
Alcoholism thrives on secrets and manipulations.....
In recovery, alcoholics are advised to exercise honesty in all their affairs, I believe......
He might as well get started now....