Thank you got the suggestions. I could probably convince him to stay in the bed as the fog has the run of the house and can knock him over.
Rachylou, that is funny. This child had no idea what Coca-Cola is. No one in the family ever drinks it. He does know about beer and coffee.
I hate to have him fall out of bed because his parents may be upset with us.

Before I learned the pool noodle trick, I would lay a body pillow on the ground next to the bed so if he fell out, he fell onto the pillow.

We ended up getting a small folding cot from Amazon that was recommended to DDIL by friends with toddlers. It sinks slightly in the middle when the child is in it and is less than a foot from the floor if he does roll out. He has used it for a nap and overnight and it was fine, although he says he prefers the Pack N Play.