Though you’ll never hear it from him, if William needs to be comforted, he’ll want to be touched. A hand on the shoulder, a hug, etc. (If he’s nearing hysterics, the best bet is to stroke his hair a bit. His mommy did it when he was a little one, so it’s kinda like the back of a cat’s neck to him)
That being said, if he sees someone in need of comfort, his first instinct is to reach out a hand. Of course, this is William, so he might not necessarily do it, but if someone’s upset and won’t let him touch them he kinda doesn’t know what to do.