It is interesting that he likes some visitors and not others - try to fathom that one out! It could be a man/ woman thing, do the people he likes have dogs, cats, other animals or are they the ones he hates? It may be tall people he dislikes, short, chubby, smelly (by that I mean people who wear a lot of perfumed products, so don't tell anyone that your dog doesn't like them 'cause they are smelly - and if you do don't tell them that was my idea!!!!!!!) people with facial hair, wearing coats or hats. Anything can be the trigger but if you can find it then it is a huge help to overcome it.

Try to feed the dog in the car if he is nervous of it.

Have you actually tried to take the dog out of the house or are you worried about what might happen?