It is not inappropriate, immoral, or a sin to serve alcohol to customers. I presume it is now a standard part of a bartender’s education to learn how to cut off someone who has been drinking too much, how to deal with a drunken customer, and how to refuse service to a known alcoholic. If not, I recommend that your mother ask for such training, but I don’t see any other reason to worry. Responsible bartenders working for respectable establishments can earn a good living.
