Praise be to Allah.
Firstly: You have done well by accepting the ruling of Islam in all cases.
Secondly: May Allaah bless your newborn and cause him to grow up in obedience to Allaah.
Thirdly: The scholars have stated that naming the child is the right of the father, to whom he is to be attributed, so he is called So and so the son of So and so, or So and so the daughter of So and so.
Fourthly: It is not necessarily the case that the mother be rewarded for some of her efforts in this world, and it is better for her to take that in the Hereafter.
Fifthly: Despite all this, it is mustahabb for the father to try to reconcile all interests if possible, and to consult the mother, but in the case of disagreement, he is the one who makes the decision.
Sixthly: For the father to honour his own father is a good deed, especially when he grows older. If he misses the opportunity to honour him with this child, he may miss out on the opportunity to do so in the future, but if he honours him with this child, he will be rewarded for that, and he may please his wife by allowing her to choose the name of the next child.
We ask Allaah to bless you with more.
Seventhly: The name Najeeb in and of itself is a good name which means noble or generous.
Al-Fayroozabaadi said in al-Qaamoos (p. 136): Najeeb means “of noble descent”.
This is a name which bodes well for the child.
We ask Allaah to protect him and enable him to grow up in obedience to Allaah, and to give you more than you hoped for through him.
And Allaah knows best.