I did post another reply on your previous thread a couple of days ago so not sure whether you have revisited it.
Anyway, in reponse to your post in my experience you just need to keep your expectations very low. Don't expect excitement when you arrive, I am sure he will be happy to see you but you may not get the response you expect. Plus you might expect any of the following, lack of physical and emotional closeness with you, sleeping for long hours, getting up for a short time then going back to bed, very quiet and within himself, he might not really want to talk in depth about
anything. Might not want to go out so expect that you might just stay around the house whilst you are there, don't try and push him to go out because you think it might make him feel better. Don't push him on anything as you are likely to get into an argument easily. Depending on his situation he may not be looking after himself very well so don't expect a smartly, well turned out person to greet you at the door, when my hubbie is depressed he bearly even brushes his hear and slops around in the same track pants and t-shirts for days on end. Everyone is different and obviously depends on his personality but you may feel that he is snapping at you when you try to talk to him. All of these are generalisations I know but I have experienced and I am sure others will have as well.
As you have mentioned before if you are going just to 'experience' this period so that you can see what it is really like living with him then all good but don't make him aware that it is an 'experiment' on your part otherwise he will definately feel like all his behaviour
is being observed. Be prepared to leave early if it is not working out but I sincerely hope it does
Keep us posted and hope things work out.