@elcho & waterskier Stop threadjacking! Whether there should be a different drinking age is not the issue here!
This site shows the various penalties and infractions for minors. You did not provide enough detail to know exactly what he is charged with. Just drinking is as follows:
“B. Consume liquor or imitation liquor, except in a home in the presence of the minor’s parent, legal guardian or custodian, as defined in Title 22, section 4002. The following penalties apply to violations of this paragraph.
(1) A minor who violates this paragraph commits a civil violation for which a fine of not less than $200 and not more than $400 must be adjudged.
(2) A minor who violates this paragraph after having previously violated this section commits a civil violation for which a fine of not less than $300 and not more than $600 must be adjudged, none of which may be suspended except as provided in subsection 2, paragraph B.
(3) A minor who violates this paragraph after having previously violated this section 2 or more times commits a civil violation for which a fine of $600 must be adjudged, none of which may be suspended except as provided in subsection 2, paragraph B; [2003, c. 452, Pt. P, §4 (AMD); 2003, c. 452, Pt. X, §2 (AFF).]”
There are added infractions for driving as a minor with alcohol in your system or for buying liquor, and those have separate penalties.
The good news is that Maine regards the drinking infraction as a civil not criminal matter. For more information, your boyfriend may want to consult an attorney in Maine. If you google Maine OIU attorney, you will see some referrals. Most offer free initial consultations.