I point you to this story by the Washington Post about how Trump's father was profiteering off government contracts to supply housing to WWII vets (one of which was Guthrie). He even wrote some unpublished song lyrics about the situation.
The unbelievable story of why Woody Guthrie hated Donald Trump's dad.
It was suggested in a youtube comment that the above song was in part directed at Fred Trump, but that seems misdirected, since it is pretty obviously directed at America's WWII foes. But I don't doubt the sentiment applied to Old Man Trump as well.