LPFM stations may engage in third-party fundraising as long as the beneficiary is an IRS 501(c)(3) non-profit charity. It must have an IRS designation. LPFM and NCE stations are limited to only one percent of their annual airtime being devoted to third-party fundraising. All third-party fundraising activity must be logged.
In large scale disasters such as Katrina, 9-11, the Great Tohoku Earthquake, etc., the Commission has granted blanket waivers to permit LPFM/NCE stations to interrupt programming to raise funds for third-party organizations. There are specific reporting requirements. This will be explained in the public notice when the FCC authorizes third-party fundraising for a particular incident.
NOTE: This advice came from a non-attorney and therefore is not legal advice. REC assumes not liability for this answer. For legal advice, please seek the services of a qualified attorney.