My husband (soon to be divorced) is a practicing alcoholic. We have an 8 y.o. what do I need to get supervised visitation.

In cases of supervised visitation, the court must find that restricted access to a child is in the child's best interest.  There is a rebuttable presumption in Texas law that the Standard Possession Order set out in the family code is reasonable minimum possession for a parent and is in the best interest of the child.  In order to be granted supervised visitation only, this presumption must be rebutted by evidence that it would be harmful to the child.  You will need to document such things as driving drunk (a DUI conviction would be evidence), any alcohol related problems (job loss due to excessive drinking for example), statements from witnesses attesting to his intoxicated behavior, and most importantly, any statements made by your son about his father's alcohol consumption.

However, even if the court found that a supervised visitation schedule was warranted, it is usually short-lived.  In other words, the court's goal is generally to achieve a Standard Possession schedule for the parties and the child eventually.  This is true because it is logistically difficult to implement supervised visitation since this usually requires an imposition on the schedule of a volunteer supervisor, such as a family member.  Paid supervisors are available, but it gets expensive.

You now need to consult with a family law attorney in your area.  He will best be able to advise you how to proceed in going about all of this.