All inclusives and alcoholics will never mix. I know the one we went to in Jamaica was a big drink fest the entire time, with the staffers encouraging people to drink, and running games with the awards being bottles of booze.
Nothing can be changed now, and it's certainly not your fault. If someone picks up again or not is up to them. Putting themselves in temptations way is something they have to learn to control, or not, up to them.
Hugs.