So glad you are here, I think getting to an al-anon meeting is a huge step in the right direction, the folks there should be able to give you solid guidance.
It is amirable that you want to keep your family together, but please consider the safety of yourself and your child, in addition growing up in a home where there is constant verbal abuse is very damaging.
As far as alcoholics go every one is different, a friends mom gets drunk every 90 days, the pressure to stay sober gets to her so she ties one on and then starts over the next day. I would say that as fresh as he is from rehab he probably cannot handle any alcohol.
I hope you will come back often and let us know how you are doing.
Please take care and peace be with you.
Bill