I wouldn't say anything about his weight/appearance. I would keep the conversation light and friendly, if he should call. I would be civil and listen to what he has to say. You have to remember, this is his journey and he needs to figure things out for himself...also, you are not his mother and for the moment, he fired you from being his wife.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
