what is the best immegration form or approach

I assume by your concern over your husband's age of 16 that you were both thinking that he might qualify for the administration's program, Deferred Action for Childhood Arrivals. Another alternative available to your husband if you are a US citizen may be the administration's other signature program, the I-601A under which you would apply for his I-130 alien relative petition; he would apply for an I-601A provisional waiver while here based upon extreme hardship to you; and upon approval, consular process the rest of his paperwork at his home country's American Embassy or Consulate. The I-601A program offers a much better choice for consular processing than prior practice under which the petitioner would file the I-130, have it consular processed, the applicant interview overseas, be denied, and only then given the opportunity to apply for the waiver. The other alternative for your husband is for him to remain in the States and await the results of this year's debate on comprehensive immigration reform.Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.  

That depends on whether your husband came to the US through a port of entry (with inspection) or whether he slipped across the border undetected.