Hi tadhg
Beyond just thinking of them, hopefully fondly, I personally don't see much reason to create or practice some ritualistic annual memorial. Is it your understanding, or your wife's, that holding some special service garners some favor with your Creator? Do either of you believe that you can obtain salvation for someone else through prayers for them after they are dead?
My father died many, many years ago and I remember and consider him from time to time. I think back on all the things, both good and bad, that we did together when he was alive. Beyond that, although he was certainly a person who was special to me, the fact is that he's just another person who has gone to the grave. He lived his life as he saw fit and I think was fairly satisfied with his life as it matured. I don't think he had a saving relationship with the Lord, but that, of course, is between he and the Lord. He was a reasonably good father as fathers go and I loved him. He was my dad. He taught me things and disciplined me as a child and I have many fond memories of things that we did as a family and just he and I together.
So, for me, remembering my dad is just something that I do from time to time. Especially when questions such as this come up. However, it is my understanding that where he will end up after the day of God's judgment is something that has already been set and there's really nothing anyone on this earth can do for him to change that.
God bless you.
In Christ, Ted