I’m getting concerned

Sooo lately my son his 2 years (Not Baptize yet) well I notice a lot that he wonders a lot like he will be playing with my daughter or doing whatever and he looks around the house a lot almost as if (you’re watching a fly that was moving around the house) it happens to my daughter too she’s 3 but my son seems to happen most of the times. I’m not sure if it’s something with spirits or angels idk to be honest I’m not sure if his something else but I can guarantee his seeing something like they will literally see something and follow it with they’re eyes. I have sometimes talk to them to get they’re attention. My husbands dad passed away 3 years ago he never meet my son we have pictures of him in our living room some with my husband. The other day my husband said he caught our son just staring at the picture we have with his grandpa who passed. I heard kids have an easier chance to see spirits or ghosts since they’re innocent and young. But idk what to think of it