The Shi’iltos at the end of P’ Toldos presents a dilemma of competing values: a person is obligated to honor his parents and must attend to their needs, but at the same time feels compelled to travel away from his parents for the sake of learning torah – which takes precedence? The Shi’iltos cites the gemara Megillah 16 which explains that the reason the Torah informed us of the age of Yishmael at death is so we could calculate the years Ya’akov spent away from home. Ya’akov spent 14 years learning before he came to Lavan’s house for which he was not punished for not fulfilling kibud av, indicating that talmud torah takes precedence over kibud.
The Netziv explains that the Shi’iltos understood the pasuk of Yishmael’s age as a gezeiras hakasuv which teaches this din; without the pasuk, kibud av would be doche the mitzvah of talmud torah. Interestingly, Yevamos 6 tells us that kibud av is a “hechsher mitzvah” and would ordinarily not be doche other mitzvos, but here, apparently it would if not for the gezeiras hakasuv.