The Panus family that I'm working on was headed by John Felix Panus and his wife Elanor Stella Linowska. Both of their families were from the Plock area of Poland and the parish of Baranowa.
John and Elanor had 6 children; 3 boys (John, Joseph, Chester) and 3 girls (Mary Rose, Pauline, and Sophie). I don't have birth dates and middle names for most of them, so I can't be sure if this Joseph is the one that you're looking for. However, there is a brother Chester and several girls in the family so it appears to be a close match to what you're looking for.
Run this stuff by your grandmother to see if it looks familiar to her.