I hope they can fix that right up for him.
One day when clipping Bella's nails, I went for her outside pinky nail, and it was not there. Some bloody residue, she had been caring for it herself, I was going to have it looked at, at her vet visit, but it grew back.
I found the nail hanging on a kitchen cupboard, kinda creepy.

Make sure there is no infection.

Good Luck.