When you try to get him to express his feelings he may have automatic reflexes to protect himself from you. That's why there may be a longer pause when he goes to answer questions from you.
Yes, I can see that.
That long pause is difficult for you because of your relationship with your mother where she wasn't there for you and your high anxiety feelings. Within that long pause you are worrying about all the potential negative things he must be thinking. When in reality he is not thinking negatively at all but is worried about exposing his feelings to you.
Long pauses have been tough for me in general. This is why I normally find message boards difficult. You don't get that instant feedback you normally would in a convo. I have always needed feedback and to know where I stand. I realize that this is something I need to work on (I know there are terms for this like "fused" or "enmeshed" or something like that.) It's just the result of having an insecure attachment style.
It's great that you had such a happy childhood. There is nothing like unconditional love from your parents.