Hi, I am looking for a 2nd opinion, a proof read on the inscription for my father's grave.

Commander Pádraig Adrian Ó Mathúna Irish Naval Service
Déag 7ú Eanair 2022 in aois a 89 bliain

So basically I'm asking are all my fadas present and correct.

Thanks
Shane

I'm surprised to see your username - if it means "the donkey", then it is an t-asal, with a t.

Déag: should be d'éag, with an apostrophe.
Eanair: in Standardised Irish this should be Eanáir.
a 89 bliain: a 89 mbliana. [In aois a naoi mbliana is cheithre fichid.]

An tSeirbhís Chabhlaigh is the Irish for "Irish Naval Service".
Commander in the Irish Naval Service is Ceannasaí (see https://en.wikipedia.org/wiki/Irish_Def ... k_insignia)

as a title ceannasaí is used with the article:
An Ceannasaí Pádraig Adrian Ó Mathúna

Writing nouns with higher numbers: the noun is often written unchanged (89 bliain) though it is pronounced as naoi mbliana is ceithre fichid (or naoi mbliana is ochtó).