Originally posted by Dixieland Dancer
We're talking about a 13 year old veteran here. I would NOT start crate training him at this point of his life.
I'm sure it wouldn't be an easy transition, but it can be done. I've rescued young and old dogs and managed to crate train them. And these are usually dogs that have lived their entire lives outside. I rescued a senior Dalmatian that had apparently been an outside dog all his life and he became very attached to his crate and would open the door to let himself in. If it means his safety, then there really isn't many other options. A wire crate would probably be easier because he'll still have a good view of the entire house and won't feel as closed in.

A baby gate is a good idea if it can be done in a safe room where he can't eat anything that isn't his.