Scared dog not habituating to people starts to growl

Question
Hello Lee,
My dog (Whiskey) will be turning three in August this year. He has always lived out in the woods with 6 to 12 other dogs, he pulls a sled in the winter and packs a back pack in the summer when we go for hikes. He listens to commands like sit, lay down, stay, he fetches stick or balls, he jumps on command and swims. He is very well behaved; I can leave fish or dog biscuits in his reach in the car and he won't touch them until I hand them over to him. His mother is a mix between a Golden Lab & a Husky and his dad is a German Shepherd. He weighs about 65pounds.

Although he's had an active life he hasn't had  much contact with the outside world besides my boyfriend and I, with whom he is awesome. When people came to the house he just stayed away.

My concern is that I moved back into my parent's house 2 months ago. Whiskey was scared of my parents and 12yr old sister at first, I though it would pass and that he would develop trust with them, but no such thing has happened. I call him near us when we are together and he accepts being touched/petted as long as I am in the same room, as soon as I go anywhere, he follows on my heel. He seems just terrified of my family (and of most stranger for that). That big dog has already jumped on my bed to hide behind me when my mom entered my room to wish me good morning. He is especially scared of fast movements. If I am not around; he will go hide in my room, or anywhere he can, and not come out until he hears my voice. My sister can go see him and pet him when I am not around and he is ok, but he will not follow her anywhere unless he is tied on a leash. If I'm not around, my mom, and especially my dad can't really approach without him growling. What worries me is that he has started to cower down less and growls when someone (especially men) approaches him and I'm not there (he will sometime growl when I am there, but I tell him not too and he backs down).

He growls with his ears back and tail between the legs. I am worried because I want the situation to improve, not deteriorate; His growls toward my dad have been getting louder, and I would not want anything to happen. He has never growled at a child, but has run away from them at times.

I think the most peculiar thing he does is that he will play fetch outside with my mom or sister, but at some point will get scared all of a sudden, with no apparent reason. He always then refuses to go in or out of the house with anyone but me. He spends most of his day outside on a long leash with a dog house and stuff, but I am worried that a stranger or child may cross the boundary by accident.

He is very friendly with other dogs, and of all the dogs he's been around, has never gotten into a fight, and he's extremely tolerant & nice with puppies.

What can I do to show Whiskey that other people are ok, that they can provide him with caresses and fun (fetch), and he should not be aggressive towards humans.

Thank you very much in advance,
K.R.

Answer
Hi, KR.

Thanks for the nice comments. I'm even happier to hear that Whiskey's been making progress.

If you need any further input, let me know.

LCK