Sorry to hear about your sad loss, when my nan died one of our boys was about the same age, we told him that nana had gone to heaven and that if he looked up into the sky for the brightest star, that was nana ha accepted that and used to look out the bedroom window to say goodnight to her, you can't ignore it as he will ask questions but kiddies are better at coping if they are told the truth, he will soon be back to his normal self, mot easy but it must be done, good luck, Ray