The first question is whether he is here legally or not. If he is here legally you can get him a green card by filing the necessary paperwork. If he is not here legally he will most likely have to leave the US and apply for a VISA at the US Embassy in Brazil.
I agree with my colleague. Assuming he entered the USA with inspection, you can sponsor him. Consult with an experienced immigration attorney or make an info pass at your USCIS sub office to receive insructions. WWW.USCIS.gov
Are you a US citizen. How did your husband enter the US? Was he married to you when he applied for his US visa? Did he make any untrue statements when he applied for the visa or when he entered the US? There are many things that you and your husband should discuss with an immigration lawyer to determine if he may be able to apply for a green card.