S.G.
Hi R.,
Sorry this post is a little late. I saw your question last week and had no ideas. Then today something came to me.
My husband goes out of town for work. Usually three weeks a month. Sometimes my dauhter has a hard time adjusting to him being gone and doesn't want to talk to him. I know she misses and loves him dearly so I put the phone on speaker phone and my hubby talks to her. Even if she runs out of the room (she usually comes back!) she can hear her daddy tell her he loves her.
Another thing we did was went to build a bear and my husband built her a special bear with his voice saying he loves her and will see her soon. He gave it to her the next time he left and she cherishes it. I know they have build a bear in Vegas. Maybe your hubby could find a time to make your son a bear.
Good luck and you, your family and hubby are in our prayers.