So, yes, I do believe he is "cutting in line," and should have the humility to stand in solidarity with, rather than standing on the necks of, marginalized communities. Your father-in-law is not climbing out of anywhere so deep a hole as the Black and Hispanic populations on this continent. Not even close.
Even the Gulag Archipelago pales in comparison to the centuries of slavery, genocide, rape, and disenfranchisement we have visited on these peoples in order to accrue the wealth that your father-in-law now has the privilege to work for.
Despite XIX century reforms dismissing serfdom in some regions, generational poverty of peasants kept them in serfdom like conditions up until end of WW2. And even after WW2 you could end in Ukraine with forced exports of food resulting in genocidal famine.
That Eastern European immigrant has family history of half a millennium or more in slave like conditions.
If you are indeed honest about it, you can personally take a step back and promote anyone you want. Demanding it from others is just self-righteous and your intentions are questionable.