Tell your friend to take the dog along to a dog training class and if one of the qualified trainers thinks it has behavoural issues, then they might be able to recommend a behavourist. There's clearly something not quite right 'gets distressed if not close to my friends husband'.
I'm not sure I agree that carrying a dog in a car requires it to be contained in a cage. If that is some legal requirement, please can you quote where from so I can read it.
My dogs travel in seatbelt harnesses and both sit on the back seat. Don't place a dog in a harness where an air bag can actuate. I do this because, in the event of an accident, the dogs won't roll round the car and kill or seriously damage the occupants, or injure themselves. Also, the dog won't be able to run off either.
When a dog is properly accustomed to a crate, the dog will view it as its den and believe me, all dogs eventually love crates. As someone else said, tell them to introduce it to the crate slowly and feed the dog in there etc. They could buy a crate cover for it too, sometimes covering the crate will quiet down an excited dog (subject to how hot it is obviously). (I do that with my SBT at dog shows because he sings like mad and when you're in a room with 400 SBT's, all crated and singing, it kind of gives you a headache).
I won't comment further on any training issues as it's impossible to see what is actually happening and I might give the wrong advice.
My dogs arn't normally allowed in our van as their place is the awning.
Keep us updated.
Lisa