There are many ways parents can bless their children, and praying for their safety is one of them.
Prayer has far reaching consequences. Its effect does not reside simply in the immediate physical locale of the one who is praying. Its effect is felt by anyone the prayer’s blessings rest upon.
There is no space or distance in Mind.
What is true in one locale of Mind is true in every locale of Mind. So, when a parent prays to know their children are safe in divine Love’s presence, protected and cared for by the intelligent and wise Mind of God, that truth will be felt by their children, even if only unconsciously. And it will have a good effect on their experience.