The pull on that bow is too long, but it's no big deal. He just needs to keep his head down. That would be good enough for now. As he grows into the bow, he can get into the habit of using an anchor point.

But, at 6, who cares. As long as he's shooting and having fun.

Here's my son when he was 5. The pull was too long for him then, but he's using the corner of his mouth as an anchor point now.