Al Allaamah Zayd bin Haadi Al Madhkhalee (rahimahullah) said:

“The greatest act of good (towards parents) is that the son whom Allaah has bestowed upon him with some (Islamic) knowledge, that from it, he offers (teaches) it to his parents as a first priority.

And this is better than being good to them by giving them money or anything other than that.

Then (it follows that) he should be good and dutiful to them with good words and good actions which pleases Allaah, then with that which pleases both of them (Parents).

[This applies to both Son and Daughter]”

‘Awn Al Ahad As Samad Sharh Adabul Mufrad 28/1