My son was just the same. He couldn't even watch some things on CBeebies because it frightened him so much. I had to be very careful of anything that was on television due to his fears.
He is 18 and overcome all his fears, he will even watch horror films , something that even I won't do
I wouldn't worry too much about your grandson, he will almost certainly grow out of it.
I think someone got out of the wrong side of the bed
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