They can confiscate the abusive drug the person if using, or admit the person to rehab, or simply apply them for therapy. They can substitute the drug for something else like say it was a cigarette, you could instead use cigarette shaped candy’s. There are quite a bit of ways to help but those are just a few.
This is the law of dominance in genetics. The dominant allele will mask the effects of the
recessive allele and therefore will be the visible trait of the phenotype. Most often, the dominant allele codes for functional proteins, while the recessive does not code for functional proteins. Dominance in genetics is
significant in Mendelian inheritance.