Oi nu nu. Oi nu nu
Rosvaseli Rode nu
Rosvaseli Mamu tata
Rosvaseli sistru brata
Oi nu nu, Oi nu nu,
Rosvaseli Rode nu.
That is Ukrainian.
The fact that your father claimed to be Polish is not unusual. Many Poles and Ukrainins had geuinly doutle identity. Born in the East but under Polish rule they were in a position to claim either nationality. I personally know at least half a dozen Ukrainian-Poles who speak both languages perfectly. They are Ukrainians when they go to a Ukrainian Hall, but Polish when there is a dance in the Polish Legion.
Note:
Rosvaseli Rode nu should be really
Rosveseli Rodinu i.e. cheer up the family