How do I get my dog companion certified as a companion for PTSD?

A friend of mine has the nastiest form of MS. He's losing mobility and going blind. He looked into the companion animal thing and is getting a service animal. He told me that there really isn't much benefit to having a "companion animal" because most places refuse the entry. By law businesses only have to accommodate service animals. Many businesses would be breaking health codes by allowing non-service dogs including certified companion animals.