Can this be considered a hook?

My parents immigrated to the US from Poland, and both of them studied in Poland as well (they got low degrees of some sort). However, when they immigrated, only my mom received her bacholers degree in the US. Would it be a hook that my father did not attend university in the US?

No

Agree with Gumbymom. Furthermore, when you fill out the common app, you will be required to give information about the level of education your parents have attained. There are many many high school students in the US whose parents are foreign and were educated abroad.

No. Very few people have hooks.