The reason I challenged portlander on your thread crofta was the simple fact that he/she is not qualified to give legal advice. The mere fact that he/she does not know the consequences in washington/orgeon for contributing to the delinquency of a minor, MIP or other statutes regarding providing minors 'access' to alcohol proves that point.
As to your particular situation, IF your boyfriend had entered the premesis with force, he would be facing breaking and entering. As such, he will only be facing larceny charges for which, in your state is subject the Michigan Penal Code 750.356 could be up to 10 years in jail and a $15,000 fine.
The entire code section can be found here:
http://www.michiganlegislature.org/law/otis.asp?objName=750.356-A