In the US Census of 1870, in Yonkers, New York, we find John Sweny, undertaker, his wife Matilda, and some of their family, Lydia, Abraham, William, Emily, Jemima, Ralph, and John. William was a lawyer’s clerk, John was ‘at the school’ and the other children worked in shops. All were born in Ireland.
When William applied for a U.S. passport in 1891, he stated that he had arrived on the Helvetia from Liverpool on 15.3.1865, age 15. There were two arrivals of the Helvetia in 1865, but not on 15 March. There seem to be no passenger lists for either one.
I believe that William, 26 years later, got the dates wrong. The maiden voyage of the Helvetia to New York left Liverpool on 28 March 1865. I believe that John and his family came on the second voyage, which left Liverpool on
12 October 1865, picked up the Irish passengers at Queenstown (Cobh) near Cork, and arrived in New York on 30th. October. John Paget was a witness at the marriage of his daughter Georgina and William Henry Talbot in Dublin on 23.8.1865, so he could not have been in New York then, and William was too young to travel alone. John, Matilda, Ralph, Lydia, Emily and John jnr. all came back to Dublin. Abraham, William and Jemima stayed in the USA.