More information is needed. How old was he when his father became a naturalized U.S. Citizen? Did he live with his father or both of his natural parents? Did he already receive permanent resident cancellation of removal? How many times was he convicted of drug possession convictions? These are a few of the many questions that should be answered by an experienced immigration attorney at an appointment or teleconference.
It is unclear whether marriage to a U.S. Citizen will make a difference at this point. A marriage should be done because people are in love and willing to spend the rest of their lives, together, even if it must be in Jamaica.
I strongly recommend an appointment or teleconference with an experienced immigration attorney.
The above is general information and does not create an attorney-client relationship.