How well did Crown Prince Rudolph get along with his paternal grandfather Archduke Francis Charles?
They practically had no real contact. He and his sister Gisela though loved their grandmother Sophie and were devasted by her death.
Rudolf didn't have much people he truly felt at ease with. One was his grandmother (died in 1872), the other was his elder sister (married in 1873)...his mother was practically always absent and his father was a total different character. So his was more or less left alone at a young age.
Did he not also have an abusive tutor for a period of time, that was finally removed at the insistence of Elisabeth (probably the only time she intervened in Rudolf's life)? I think I remember reading that. Carol II of Roumania also had an abusive tutor who was only removed from his life too late.