Informations You found are correct! The three brothers was named Boles³aw, Eugeniusz and Maksymilian.
Boles³aw was born around 1880. I found him on Canadian Passenger List, 1907 and in United State Cenzus, 1930. He lived in New Castle, Lawrence, PA. He had wife named Maria and three kids: Adam, Helen and Annie W.
Eugeniusz was born around 1894. He arrived from Hamburg to New York in 1914.
Maksymilian was born around 1885. I saw him in United State Cenzus, 1920. He lived in this time in Lawrence, PA.
Their father was named Piotr and mother Maria or Marianna.