Whittling advice

My son ( 6 ) announces he would like to learn how to whittle. Where do I start to help him persue this interest? Any advice on knives, wood, equipment etc would be greatly appreciated. Don't let his tender age fool you, he has incredible toolmanship already, but I really like the idea of him exploring an area that may require a great deal more patience and gentleness than he is used to
thanks in advance !
V🌸