I seem to recall discussing this NY State age thing with another parent. The financial responsibility of the minor until age 23 is a bit of a misnomer. It's mostly for purposes of child support, but I can se it being used in cases of property damage as well. However If he chooses to move out due to refusal to follow reasonable rules, then he is considered emancipated.
http://www.avvo.com/legal-answers/under-new-york-child-support-laws--at-what-age-doe-15584.html That answer appears to be three years old, so it may have now been changed to 23, but again, there are exceptions to the rules.
