Hi February13
I can tell you as a recovering alcoholic, sober for over 4 years, that what you see in public is the tip of the iceberg.
Can you visit your friend at home, unannounced, see for yourself what's really going on? If your friend was sober for a few years and relapsed, she may be in a world of trouble and indeed need some help.
If this were my friend, I would act like a friend and make sure everyone was safe, especially this innocent child.
Your actions may very well save them both from a disaster that cannot be undone.