My son wants to play Pokemon GO, is it safe for a 5 year old ?

As long as you are around when he is walking around "catching Pokemon", it is safe! It's a very fun and educational game. Alot of math, strategy and creativity is needed to successfully play the game. Just make sure you hold his hand when he's playing in public places especially near roads and bodies of water. If you want to be extra safe, only let your son play the game under adult supervision. I've been playing it for some weeks now in Sweden and lots of kids play it, together with their parents and even grandparents!