I don't believe that marriage will solve the problem for the long term, especially, if they're young. Most of us, who's parents are from the older generation, didn't do their best to stop a young marriage, i.e. - the parents know that it's not the best interest of their young daughter, but do to saving face of the extended families, the parents proceed with the marriage (it's only for those who were wife-napped).
If i have a daughter (don't have one yet) or if my neices were wife-napped, i would go the grooms house and talk to the young man and his parents that if he's really interested in my daughter, they can date and postpone marriage until after they both graduates from college or in their mid 20's.
It's true like you said, your neice have a life ahead of her and she's too young for marriage. I oppose to young marriages.
When I see a young lady married, i feel sad for her, because she has thrown her whole life away, and will submit her life to fulfill the role of a married woman, especially if the young lady's mom is also a teen wife. There's so many unlimited potential for all our children to succeed prior to marriage. Most of young marriages turned into divorce household or unaccomplished goals due to obligations of being a parent, daughter-in-law and etc.
There's a purpose why we live in America, to live the American dream and have our children be successful.
If I recall correctly, back in the 90's, if a young lady was wife-napped and her parents called the policed to retreive her, the extended families and/or grooms side would say that her parents are cruel (pem pem), but i realized that it's not because they're pem pem, they're concern about their daughter's future.