What is the ruling regarding someone whose father did not allow him to perform I'tikaf for unconvincing reasons?

I'tikaf is a Sunnah (definition), while honoring one's parents is an obligation. A Sunnah does not supersede an obligation, and an obligation takes precedence over a Sunnah. If the parent orders one to abandon I'tikaf because they need their son, then it is better not to perform I'tikaf, as the parent sees the justifications for that. However, if the parent does not provide justifications for preventing I'tikaf, then obedience to them is not obligatory in that instance.