unique, I don't know you or him or your circumstances. There are several commonalities I have seen from others who have left the organization, one way or another.
A body of elders called a Judicial Committee holds a sort of hearing with the person who is accused of whatever wrongdoing that might cause a disfellowshipping. Some infractions include but are not limited to, sex without mariage, homosexual relations, adultery, smoking, drugs, drunkenness, gluttony (this one is NEVER enforced), spiritism, interfaith, oral/anal sex with one's spouce, masturbation (again.. not enforced), apostacy, refusal to comply with the elders (a sort of generic grab bag to get a person if nothing else works). The elders will typically not actively want to disfellowship the person. The Judicial Committee hearing is more to scare the person into repentance. He has to agree to change whatever he did that caused the problem, and then there is some prayer, and quite often some form of probation (either a private or public reproof with restrictions upon the person's "priviledges"). In short he'd have to dump you, confess to his wife, beg her forgiveness, stop smoking, pray to Jehovah for forgiveness, turn in anyone else who is a JW who was involved in any of these wrongdoings, and not share his views about the JWs with anyone else. Oh, and he get's an appeal. The appeal is a meaningless repetition of the previous paragraph and always ends the same way. It is rarely done, but its in the rulebook. The rulebook is private. Elders can see it, lay persons cannot.
The ramifications of being disfellowshipped are that his former friends and family who are still Witnesses will no longer be able to talk with him (or at least, not in any meaningful way). They are to view him as spiritually dead. When a person's entire life is built up around being in the Jehovahs Witness culture, then being disfellowshipped is viewed as a terrible punishment. It is, in effect, exile.
He could also just say "I'm not a Jehovahs Witness anymore", in which case he would be considered dissassociated. There really is no difference in how dissassociated persons are treated from disfellowshipped persons. Depending on the elders in his congregation, it might be harder for him to come back, if he chooses, after dissassociation, then after disfellowshipping. Some do come back. Dogs smell their own shit, sometimes also.
Right now he probably wants it all: your love, his family, his friends, his stability. I can tell you firsthand, that balancing act doesn't last forever. That's all I have to say about it.
