My H also has a closet full of clothes here. I think I asked him in September if he still wanted them - can't remember what his reply was - something like, there's no rush. I haven't forced the issue. If and when I ever move, I'll throw them (literally) in a box and leave them here for him to collect himself. He asked S5 to bring him his tennis racquet last week. I really didn't want to since I'm not responsible for bringing him his stuff that he left behind (although I usually drop the kids off at the house for him). Luckily, S5 couldn't get to it in the storeroom and he didn't ask me to help since I was already in the car.
I say leave the clothes there until it's truly truly over.
