Like his son Donald, Fred Christ Trump was a very successful real estate developer. (We've previously seen an old Depression-era supermarket he built.) Unlike his son, however, he had a reputation for modesty and frugality. According to his family, he would regularly visit his construction sites at the end of the day, still dressed in his suit, and would walk around collecting unused nails to make sure they didn't get wasted. He would also often handle the pest extermination duties in his buildings himself, just to save money. Here at All Faiths, there is only one indication that his gravesite belongs to a family of above-average means: while most of the footpaths in the cemetery are cracked and/or partially covered with dirt, the path leading to his headstone is very smoothly and freshly paved, but then quickly returns to oblivion once it passes the family's graves.
UPDATE: Okay, maybe Fred wasn't so different from Donald after all.