Looking for Kustowski

I have pretty much located everyone on my mother's side, but my father's side remains a mystery.
His name was Alexander Kustowski, he and his brother Stanley came over from Danzig together.
I have never been able to find any record of him on a ship or any record of a Kustowski family in Poland.
I know nothing about my paternal grandparents, he would never talk about them and that has always bothered me, like maybe something terrible happened and he didn't want to talk about it.

Kostowski probably originated as a toponymic nickname describing an inhabitant of Кустово. There are several localities by that name in Russia, some may have been within the territory of the sprawling pre-partition Polish-Lithuanian Commonwealth.

Thank you

Sammie
I am going to assume that your Father and uncle came over to the usa. Did they become citizens? If so you want to locate a document called Petition for naturalization or Declaration of intention. This document will state the ship your father came over on and the date he came over as well as the last known address (it is usually the town not the address) at which he was living prior to coming over. It also list where your father was born. Good luck.

Sammie
Are you sure that Alexander Kustowski was born in Danzig? There is a corresponding dataset on familysearch.org:

Alex J. KUSTOWSKI
Birth Date: 14 Nov 1924
Death Date: 4 Feb 2006
Social Security Number: 363-20-4795
State or Territory Where Number Was Issued: Michigan

Death Residence Localities
ZIP Code: 48040
Localities: Marysville, Saint Clair, Michigan

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Ancestry.com has additional data:

1930 United States Federal Census

PreviewName: Alex Kustowski
Age: 33
Estimated Birth Year: abt 1897
Spouse's Name: Nellie

Name: Alex Kustowski
Spouse: Nellie
Birth: abt 1897 - location
Residence: 1930 - city, Wayne, Michigan

Name: Nellie Kustowski
Spouse: Alex
Birth: abt 1901
Residence: 1930 - city, Wayne, Michigan

Name: Edward Kustowski
Birth: abt 1923
Residence: 1930 - city, Wayne, Michigan

Name: Wanda Kustowski
Birth: abt 1924
Residence: 1930 - city, Wayne, Michigan

Name: Alex Kustowski
Birth: abt 1925
Residence: 1930 - city, Wayne, Michigan

Name: Frank Kustowski
Birth: abt 1927
Residence: 1930 - city, Wayne, Michigan
1920 United States Federal Census

Name: Adam Kustowski
Spouse: Sophie
Birth: abt 1882 - location
Arrival: year
Residence: 1920 - city, Wayne, Michigan
1920 United States Federal Census

Name: Sophie Kustowski
Spouse: Adam
Birth: abt 1890 - location
Arrival: year
Residence: 1920 - city, Wayne, Michigan

Some more:

Added information in OneWorldTrees:
Name: Alexander Jerome Kustowski
Birth: 14 Nov 1924 - Hamtramck, MI, USA
Death: 04 Feb 2006 - Port Huron, St. Clair, MI, USA

Seems as if your father was born in the USA and your grandparents - Alexander Kustowski and his wife Nellie - immigrated. Or did I misunderstand your initial posting?