The Trump family’s medical insurance was provided by the company owned by Donald’s father, Fred Trump. It covered Donald, his siblings Fred Jr., Robert, Maryanne, and Elizabeth, as well as their families.

Donald’s brother Fred Jr. died in 1981, but had a son, Fred III, who went on to have his own child, William. William had suffered multiple seizures and other medical issues since birth, and developed cerebral palsy. He required perpetual care, and medical costs were in the hundreds of thousands of dollars.

When the senior Fred Trump died in 1999, his assets were distributed primarily among his living children, which meant considerably less was given to Fred III and his family. He filed a suit alleging that Donald and his siblings had abused their father’s Alzheimer’s and growing dementia to influence Fred Sr.’s will, which they helped draft.

Trump responded by removing his nephew and nephew’s infant son from their insurance. Fred III said of it, “I just think it was wrong. These are not warm and fuzzy people. They never even came to see William in the hospital. Our family puts the ‘fun’ in dysfunctional.”

When asked about denying his nephew medical coverage, Donald said, “Why should we give him medical coverage?” In response to being asked if his reaction was “cold,” he explained, “I can’t help that. It’s cold when someone sues my father. Had he come to see me, things could very possibly have been much different for them.”

In an interview with another reporter, Donald said “I was angry because they sued,” but that eventually lawsuit was settled “very amicably.”

The Daily News – INSIDE TRUMPS’ BITTER BATTLE Nephew’s ailing baby caught in the middle
The Atlantic – Donald Trump’s Cruel Streak
The New Yorker – What Sort of Man Is Donald Trump?

Young Donald Trump was notorious for repeatedly getting into trouble, both at school and around his neighborhood. This was one of the reasons his parents send him to New York Military Academy, where he was for five years.

In a discussion with his biographer Michael D’Antonio, Trump noted how much he enjoyed fighting:

TRUMP: I went to New York Military Academy for five years, from the year before freshman.

D’ANTONIO: So eighth grade on?

TRUMP: Yes.

D’ANTONIO: Whose idea was this?

TRUMP: Well, I was very rebellious and my parents thought it would be a good idea. I was very rebellious.

D’ANTONIO: How did it evidence itself?

TRUMP: I was a very rebellious kind of person. I don’t like to talk about it, actually. But I was a very rebellious person and very set in my ways.

D’ANTONIO: In eighth grade?

TRUMP: I loved to fight. I always loved to fight.

D’ANTONIO: Physical fights?

TRUMP: … All types of fights. Any kind of fight, I loved it, including physical, and I was always the best athlete. Something that nobody knew about me.

Trump also told his biographer that his temperament hadn’t changed since the first grade.

Politico – What I Learned Writing Trump’s Biography
The Washington Post – Confident. Incorrigible. Bully: Little Donny was a lot like candidate Donald Trump
The Week – Donald Trump’s childhood classmates remember him as a bully