With Bogie's age and he is a large breed, it's no surprise he is limping and having trouble with his legs.
Maybe see about the tranquilizers like Karen suggested, or see if there is a vet that will do a home visit. I know you can't do x-rays in your home, but it could be a start.

My 8 year old Australian Shepherd is limping in both of her back legs, but still runs full speed outside with her "brother" too.

I hope you can figure something out for Bogie.