I think there are several issues not addressed. One is understanding slavery. In history slavery was an option to prisons. If one stole, was caught, and could not repay that which he stole he was sold into slavery to pay his debt. If one came into any financial problems in which he could not pay his debt, he was sold into slavery to pay it. This was not generally for a lifetime, but until the debt was paid. In ancient Sumer slaves were able to own property, and conduct business in their own name, much like the slaves, oops I mean citizens, in the United States. When your labor is taxed, i.e., part of it belongs to another entity, be it a person, company, or government, you are slave to that entity.
Parents most definitely own their children, until they reach the age at which they can support and provide themselves. Until then the parents have a right to their labor. Parents, which is inclusive in ownership, have a resposnibility to maintain that property. If the owner wants his property to perform at its peak, he needs to make sure the property has what it needs. In the case of a child, that means proper nutrition, and good examples of good behavior. In getting the child to perform slave labor, e.g., taking out the trash, etc., the child is learning to take care of him or herself. In performing this slave labor, or chores, the child helps pay for his upkeep.
About the drugs, a question that was not addressed was, do the parents consume the drug? My mother was like most, taking over the counter drugs. Early in my life, about 13, I decided I did not want to take them. When I got a cold I did nothing for it. I let it run its course naturally. After a number of years the severity of the cold lessened, until I did not get them anymore. The last time I had a cold was in 1982. I cannot remember the last time I had the flu. I do not get flu shots, or any other shots. I do not even take aspirin. I do not get headaches.
As much as one may want, he does not have the authority to tell another how to treat his property. If the owner abandons that property, then another, if he wants to take the responsibility for ownership, may claim it. However, because the owner is not in the immediate presence of the property does not constitute abandonment. Just because the owner is not on his real property does not give others the right to homestead it.
I do not do meth, therefore I would not give it to my child. I do not take man made drugs, therefore neither would I give them to my children. I do drink beer, and if my child at age 5 wanted a drink, I would likely give him a taste. I would not give him own his own bottle or can. In years past in Europe, and probably today, children were given wine mixed with water to drink, the younger, the more water.
The child learns from its parents through imprinting. Raising a child is a job, not a hobby. By looking after the best interest of your property, you are looking after your own best interests.