Article continues below advertisementDonald Trump may be the self-proclaimed hardest-working president in history, but he still has time to entertain his grandchildren. On Thursday, December 18, the 79-year-old POTUS was joined by his son Eric Trump's kids in the Oval Office, where he showed them his renovation plans for the White House.Eric's wife Lara, 43, shared snaps of Donald with her son, Luke, 8, and daughter, Carolina, 6, along with the caption, "Just being a grandpa.