I expect the half-hearted things he does are out of the pressure he feels not to hurt you and wanting to feel like a good guy.
You want to see them as signs of his imminent return to you. Has he said that they are? From what I understand, the answer is no. So, his hugs are probably meant to comfort you through that pain. This is just one of the many reasons it is not a good idea to rely on your estranged spouse for comfort.
If he is not in the R to the degree you would like him to be, you shouldn't be there either. Back off.
