Antonina (my paternal grandmother) was not listed as a step-daughter in a census in Massachusetts. She was listed as Petras Banakauskas's step-daughter in the Cilciute family tree on Geni.com. As far as I know, Terese and Petras (who married in 1896 in Nedzinges, Lith according to a note attached to Petras' profile in the Cilciute family tree) never lived in the US and both most likely died in Lithuania. Based on this info, I think it is safe to assume that Jokubas also died in Lithuania. I don't know how exact the info is in the Cilciute family tree but there are no children listed for the union of Petras and Terese. The only child listed for Petras is his step-daughter, Antonina. .
Hope this helps clear up a little of the confusion.