Is there any bleeding?
Is the nail still on or did it fall off?
Hi,First off you will need to clean the foot throughly with soap and water. Rinse all the soap off. Then rinse the foot in a mixture of Peroxide and water to kill any bacteria or germs on the foot. Do this twice a day.Apply a antiseptic cream such as Neosporin with pain relief and wrap the foot in gauze. Use surgical tape to keep it on. I would then recommend using a small white sock to place over this and apply it with tape as well to prevent him chewing it. Getting him to hold still can be tough you may want to call someone to help you. Otherwise choose a small area where there is less room for him to move around and get him calm and lying down. Grasp the foot and hold on while trying to apply the sock and tape. Wrap the surgical tape from top to the bottom of the foot then around and back down under the foot again to secure it in place to prevent him from walking out of it.You will need to keep this clean and dry to prevent any infection. The rest of the nail will likely break off over the next few days but it will be tender for your boy.