This helps explain why Fred (uh ... "possibly") went through so much trouble to get Donald declared medically exempt from service in Vietnam. It wasn't out of fatherly love; it was because he didn't want his tax loophole to be filled full of actual holes outside Khe Sanh.
In 1990, Trump Castle was in dire need of a quick cash infusion. How could a casino not have stacks of cash laying around, you ask? Because Donald's other casino, the Taj Mahal, had defaulted on its debt and was monopolizing the family's coffers. Donald asked his dad to bail him out, which he did, to the tune of $3.3 million. In order to avoid having his money get scooped up by the Taj Mahal, however, Fred sent one of his guys to buy up $3.3 million in casino chips down at the Castle. This payout would -- assuming no one ever spent those chips -- provide the Castle with some cash to see off its interest payments. If you think that this sounds a little shady, good news! The New Jersey Casino Control Commission did too, calling it an illegal loan that needed to be repaid. (Donald and the NJCCC eventually settled on a repayment of $65,000.)