My children tell me that when I sleep, I be calling their father as though he is in the room with me. He has been gone 16 months. I can't remember anything of it. What do I do about it?

This is a long process. Maybe seeking some counceling will help with any issues. There are support groups online also.

Maybe you are calling him in your dreams to come to you.. sometimes he might. When my friend died, I saw him several times in dreams, I never knew when to expect it. Maybe your subconscious is trying to reach him and you are in too deep of a sleep to realize it. Has he visited your dreams at all? He is always with you and even though you cannot see him, doesn't mean you don't sense or feel his presence. Maybe you should tell your children that. May they be comforted in this thought of him being ever present in your lives, even when they can't see or touch him. His body isn't here, but his spirit always lives on... At least that is how I have survived a recent death. When I relaxed my mind and body and focused on him, he would come to me. Especially within the week after he died ands ometimes when I was wide awake, I could feel his presence over me. I cannot explain it.
My advice would be to relax with it and tell your children that you are finding ways to communicate with their dad and they too can do the same. Whether in their own minds or out loud. The healing process is long, difficult and different for everyone. There is no right way to grieve or to believe.