their licensing laws permit children into night clubs
The laws vary by state but as a general rule, children are not allowed in establishments that serve alcohol unless they also serve food. Even if said establishment serves food if it is considered a nightclub/bar children are not permitted after a certain time in most states - children are not permitted in nightclubs/bars at all in some states.
Laws are even more varied when it comes to child performers. Here are NY's (for Desmond's Three Dollar Bill performance perspective).
New York (as per US Dept of Labor)
Updated Jan 2019
Models under 18 need permit from educational authorities/ Performer 16-17 needs employment certificate/ performers under 16 need permit from mayor or chief executive
To obtain certificates and permits need: written parental consent (exceptions for emancipated children), proof of age, and a certificate of physical fitness; separate procedures are in effect for New York City and for the remainder of the State. Sec. 7-7.1 Estates, Powers and Trusts Law - Courts may require a portion of earnings be set aside for the minor in a trust.
Source: www.dol.gov/whd/state/childentertain.htm
Considering the aforementioned, I wonder if his parents (1) obtained a permit from mayor or chief executive as he is under 16 and (2) followed protocol according to NYC re: physical fitness certificate etc.?