How to honor jewish father’s memory ?

My father is Jewish. He passed away 1 year ago. He used to pray for his father once a year. Can I do the same ? What would be the right thing to do ?

My mother is not Jewish. Therefore, I am not, as the Jewish identity is passed through the mother.

Edit: Also, what happens if I miss the anniversary by a day or two? I used chat GPT to give me the Jewish date based on the date he passed away, and it was wrong by a few days.