Can anyone suggest a next step or a place in Poland to continue my search on his family there?
You'll find a little bit here in English about village Trzebownisko, Gmina (commune) Trzebownisko, Rzeszów County, Subcarpatian Voivodshop. It lies 7km NE of Rzeszów, a regional capital of the voivodship,
en.wikipedia.org/wiki/Trzebownisko
Much more is provided in Polish version of wikipedia:
pl.wikipedia.org/wiki/Trzebownisko
The village is also a seat of local parish. However this is a comparatively new parish, established in 1945. It is unlikely that you will find any 19th c. certificates there. In older times Trzebownisko belonged to
Parish Staromieście, 4 km away. Staromieście is now part of City of Rzeszów.
St. Joseph Parish in Rzeszów-Staromieście does not mention anything about their archives. Their address and telephone contact is here: parafia-jozef.rzeszow.opoka.org.pl/kancelar.html
I suspect that all those documents are now accessible for Registry office or another archives:
Urząd Stany Cywilnego w Rzeszowie (Registry Office in Rzeszów) has the following archival resources, pertaining to Staromieście:
Birth books, Roman-Catholic, 1879-1902, 1902-1942, 1942-1945, Staromieście
Marriage books, Roman-Catholic, 1876-1909, 1909-1932, 1932-1945, Staromieście
Death books, Roman-Catholic, 1896-1945, Staromieście
Their adddress, telephone and email are here:
bip.erzeszow.pl/wydzialyurzedumiasta/urzad-stanu-cywilnego
Older marriage records 1786-1893 can be found in
National Archives in Rzeszów:
baza.archiwa.gov.pl/sezam/pradziad.php?l=pl&mode=showopis&id=38419&miejscowosc=Trzebownisko&gmina=Trzebownisko&wojewodztwo_id=54&wyznanie_id=23
Similarly,
older birth records 1860-1902 are in here:
baza.archiwa.gov.pl/sezam/pradziad.php?l=pl&mode=showopis&id=38416&miejscowosc=Trzebownisko&gmina=Trzebownisko&wojewodztwo_id=54&wyznanie_id=23
Address, fax, phone and email are provided above.