3 Torrison siblings from Oslo to US in 1912

Christianna Torrison, her brother, Alfred Torrison and a sister (do not know her name). They were born in the late 1880 and came to Boston in 1912. Christianna may have been married and widowed in Oslo and may have left a sick child behind with Christianna's father. The child's name may have been Nina. Christianna died of tuberculosus in 1929 and Walter died from heart attack in 1928 leaving behind 8 little kids in Weymouth, MA. Christianna's father was a cabinet maker in Oslo. I would like to find out who Christianna's parents were and what happened to the child, Nina. I have also seen Torrison spelt different ways: Torreson, Torresen, Torrisen. Thanks