Keep the pup on the leash when hubby comes home so he doesn't learn to habituate the behavior of running and hiding when he enters the room.
Then after hubby has a chance to relax and unwind, he needs to take the leash and bring the pup up on the couch or get on the floor with him and just relax. Do not let then pup leave the area (hence the leash). Hubby needs to NOT pressure the pup into interacting with him. Simply be together and try to relax. When the pup gets brave and shows interest he can gently rib the side of the pups face and then stop. Then a few minutes later do it again. Each time the pup realizes he means no harm and it actually feels good, he relaxes and starts to breathe. Hubby needs to become his safe, big friend and then we can look at creating a relationship built on love, trust and respect. But right now we have to focus on trust.
It would be good for you to show the puppy that you trust your hubby as well. When he sees you are happy to see him, and you enjoy his company then the pup will watch and reflect that too.
Be sure NOT to coo at the pup when he is acting nervous. Only praise him when he is acting brave - reward that!!
It can be frustrating and challenging to work with such a sensitive and reactive little guy. I just worked with a little 6 yr old Chihuahua who ALWAYS has to be muzzled and tranquilized to get his nails done. Today, with the right prep work and no muzzle or tranq's, I did his nails in seconds and he didn't fuss once. I point this out because if you do things the right way you can get great changes quickly.
Love Them & Lead Them,
~Elizabeth & Doug
Dog Training the Way Nature Intended