He gets very distressed and barks incessantly when anyone leaves the house. Even the jingle of keys or when you stand up and put a jacket on sets him off. He also won’t go for a walk unless at least 2 people in the house go with him. The only exception is my dad who he will walk alone with.
He’s just never content unless everyone is at home. Are there any ways we can help him to get used to being separated for periods of time?


Exposure therapy.
Keep doing it, and telling the dog it’s ok when you get back and give them a treat. But don’t make a big deal about it. Just a quick good boy and a treat while acting calm.
Have one person take him on a “walk” for like two minutes and do the same. Reward the dog and show him that brief separation isn’t a big deal, then work up the time apart.
It helps if you make two “goodbye phrases”. One used for brief separation, one for long. A big thing is they have no clue when you’ll be back. And if you stick to basic phrase for short/long, the dog will quickly put it together.
If he knows someone is leaving but said the “long” goodbye, hell be less likely to freak out they’re not immediately back