After searching for a little bit, the boys found him.
It looks like he may be stuck in the kitchen.
To make your elf in a bottle, you will need an empty dry water bottle (or a clear, cleaned soda bottle), sharp scissors, x-acto knife (optional), and maybe clear tape. Gently peel back one side of the label. If you have to, you could probably cut it and then tape back into place. Use the scissors or x-acto knife to poke a slit into the bottle. You want the slit to be covered when you put the label back on. Use the scissors to cut 1/2 to 3/4 around the bottle. Leave some of the bottle intact. If your bottle isn't completely dried, this is a good time to dry it. Gently fold your elf up and place inside the bottle. Close the lid. If needed, apply a small piece of tape to help keep closed. Reattach the label, making sure to cover the cut. My label was still sticky but if yours isn't, use a s small piece of tape to reattach the label.