What are the odds of being deported after serving time for a trafficing charge

US immigration laws deal very harshly with drug trafficking. There is a very good chance that your friend will be deported unless he is a US citizen. I suggest that he seek the services of a good immigration lawyer. He will likely be placed on an immigration detainer hold and processed for court hearings.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.  

It is very likely he will be transferred to immigration custody once he finished his sentence.  They will issue him a notice to appear in immigration court (which starts the removal/deportation process).  Whether any relief is available to him will depend on the unique facts of his case and only a lawyer paid to evaluate his case could properly tell you what he changes of success will be.