An immigration attorney is extremely advisable in your fiance's case! A good attorney can help him at his bond hearing or request another form of relief that he may be eligible for. He is convicted of an aggravated felony of drug trafficking which could result in a permanent ban from the US. This is serious and he should not go it alone.
www.gassonlaw.com - Disclaimer: This a general answer to your legal question. Unless you have a signed engagement letter with me, you should not consider this information to be legal advice.
Based upon these facts, it appears that your fiance was convicted of the crime, not just merely charged. There is a big difference. While you indicate there is a separate issue as to his criminal charges, that is one that begs answering.
If he has in fact been convicted then it appears that he has been convicted of an aggravated felony for immigration purposes which severely limits the relief available to him. What options may be available cannot be determined from the limited information presented here and this forum is not the place to get case specific advice.
You are correct to be concerned about your fiancee simply wanted to "sign his deportation." I have met with many clients who have done so only to later regret it as it forecloses options which may become available in the future. Consult with an experienced immigration attorney who can review the specifics of the case, advise you and your fiancee as to the options available, and recommend how best to proceed.
While this answer is provided by a Florida Bar Certified Expert in Immigration and Nationality Law, it is for general information purposes only and an attorney/client relationship is neither intended nor created. You should seek out qualified counsel to review your case and provide you with advice specific to your situation. Call +1-561-478-5353 to schedule a consultation with Mr. Devore.