What does the sister do with her fiancé, the maintenance engineer on tourist ships?

Maintaining tourist boats is permissible if they are for leisure and no forbidden acts are practiced on them. However, if forbidden acts are practiced on them, such as intermingling and drinking alcohol, then it is not permissible to work in their maintenance, due to the assistance this provides in sin and transgression. Allah Almighty says: (And cooperate in righteousness and piety, but do not cooperate in sin and aggression). If the fiancé works in this forbidden field, he should be advised. If he persists in his work, the engagement should be dissolved.