If Hasan was born in what is currently referred to as “the west bank” area of Israel, it would have been called Palestine in 1955. Why, that region was under the control of Jordan and was not a part of Israel. The “west bank” did not become Israeli territory until the 1967 war, when Egypt, Syria and Jordan attacked Israel — the “Yom Kippur War” is how it is remembered. The Israeli Army took Jerusalem and all of the west bank Jordanian territory after a couple of days battle with the Jordanian Army. King Hussein later spoke with regret about how he let himself be convinced by the Egyptains that the 3 countries could defeat and occupy all of Israel.
You are correct, except it was the Six Day War, not the Yom Kippur War. From 1949 to 1967 Jordan occupied the West Bank, and for 18 years nobody clamored for an independent Palestine there.
Not to be pedantic but.... 1967 was the Six-Day War, when the Jordanians foolishly joined the Egyptians and Syrians in attacking Israel, mostly whipped up by Nasser. It was in that conflict that the Israelis fully recaptured Jerusalem, the West Bank, and the Golan Heights.
The Yom Kippur War took place in 1973.
In 1946 the British-administered Palestinian Mandate still existed, so it is not inaccurate to say Hasan's parents were from Palestine.