This is a popular question. Can the deceased see and hear us when we visit graves?
As for the deceased being able to see us when we visit the grave then there are no authentic hadith or verses that say the deceased can see us.
There is a difference in opinion on whether the deceased can hear us. There is an opinion that they can hear us and there is another opinion that they can’t hear us. What everyone agrees on is that dua should not be made to them regardless of whether they can hear us or not.
We should make dua for the deceased though. This is permissible.