I'm totally with Jean on this one. I'd get him checked by your vet first. Make sure there isn't something going on medically.
My husband recently broke his leg. He is at home, in a chair or on crutches. All of my dogs have had personality changes. My normally stable GSD is showing signs of resource guarding my husband (with the other dogs). My normal crack puppy Lacy is now a lump of mush when on my husband's lap. My doxie won't leave his side. And my cranky old Golden won't come near him. All things I would have NEVER believed if I didn't witness them on my own.
Hondo Von Dopplet L Bauernhof "Hondo"- GSD
Lilie's Tug McGraw "Tug" - Golden Retriever
Maggie - Mini Dachshund (Rescue)
Lonestar - Texas Blue Lacy
Funyon, Ashe, Soot - Barn Cats
Scooter /1/2 Arabian, Shadow, Katie / APHA