I am amazed that there has been so many serious replies to your post. If any of my sons were contemplating taking any of my grandkids, at age 8 to Africa, I'd be asking what caliber and rifle would be best to only wound my son enough to put the plains game hunt on hold for ten years or so. I would tell your "friend" to get his head out of his ass, go to Africa to hunt if he wishes, but leave his 8 year old home. I'm sorry to be insulting, but I am appalled by the scenario put forth by you about taking an 8 year old to hunt in Africa.
Steve