Hi Roberto2010
I’m so sorry for your loss. My dad died a long time ago but I still remember the raw pain.
My son is older, but set up sounds similar.
i would suggest be honest with your son, say dad is working. Maybe they won’t be at school up until Father’s Day so he may not see / hear friends talking about the day. I also think adults see more than kids do in terms of family set ups when out etc.
Maybe ask him to make a card for dad you can post beforehand. Could he FaceTime his dad in the evening?
You could also ask if they want to make a card for grandad? You could either take to the cemetery or have a picnic in your garden where you remember him but then make it about the children.
Whatever you decide to do, the day will be painful, but your children will give you a reason to smile.
Stay strong and stay safe x