Here's my two sense. My daughter's father is the same way. Not in her life by his choice and lives in the Pacific Time Zone. It has been like this since she was 2 and she is now 7. I have created this bin for her where all her projects and school stuff go. The first year or two was hard with Father's Day around, not knowing what to do with the card or whatever she makes in daycare. On the other hand, it didn't feel right to not let her participate or make judgement towards it. She was/is still young that I still let her have that purity and she thinks she is saving the world. So whatever she made, I threw in that bin and I still do. And at 3, questions never arose and out of sight, out of mind. Now when she gets older and if she chooses to pursue some kind of relationship with her dad, she will be able to give them to him, be reminded of what she made and her younger years, or know that her mother really cared and saved everything.
Now that she is 7, she is starting to question why her Daddy isn't right, why he doesn't visit, why he doesn't call, and etc. Sometimes I want to scream and tell her everything but I know it's not the right time, def. not at 7. So I simply say, Im sorry hunny, but he lives far away and he will visit when he can. And we move on to doing something else. I am sure as she gets older, this answer will stop working and I will figure something else out.
Well good luck with whatever you decide to do. He is only 3 and most likely not remember.