Great Pyrenees Question

Great Pyrenees are natural guard dogs. It could be that yours does not trust your grandson and thinks he's protecting you. To stop this, you might want to VERY SLOWLY familiarize your dog with your grandson. Try to make your dog associate your grandson with positive things. i.e. Ask your grandson to come with you when you walk your dog.

I have read also to try this: Have your grandson walk past and toss a treat to your pup from a distance about 6 feet, if your pup acts calm then praise and repeat the process having your grandson get a bit closer each time. Dont push it though. Also a favorite toy tossed to the pup by him is also good. As the other person stated, they learn by association. Dogs can also sense tension or fear so ensure everyone involved is calm during this exercise. Good Luck!