Trump's Grandfather died in 1918 (one of the first people in New york to die of The Spanish Flu which killed 50 million worldwide then)

 

Died	May 30, 1918 (aged 49) New York City, U.S.

So, his son Trump's Father was left with a lot of money and invested in real estate starting at a very young age. this probably didn't help Donald Trump either who obviously got Narcissistic personality disorder from extreme Trauma as a child which is a mental illness defined by a complete lack of empathy or sympathy for the suffering of others worldwide. Hitler also had this Trauma induced mental illness.