SO looking for assistance *trigger warning*

I have been dating my girlfriend for the past year and knew about her did shortly after we began dating. I've met a majority of her current alters and have since begun to date one of them (after much discussion all the way around.)
They are co-conscious.
This particular alter is the physical protector. He deals with some of the past relationship stuff and a lot of other nasty things.
This is what has happened as I've seen and been told.
About a month ago he convinced her to give him host to give her a little bit of a break to deal with some things. It wasn't the first time he has been host but it was the first time since they had become co-conscious. He had difficulty dealing with hearing and feeling everything and he started to go a little crazy (his words). She took it back and we went on with life but he wasn't ok. Since then he has found it difficult to deal with anything and he hasn't felt well.
I found out today from the ISH that some of the "boxes" he carries have opened and he can't get them
closed again and is stuck living through them over and over again and it's not getting any better.
We are kind of at a loss as to what to do. The ISH told me he needs to accept help from others like distractions and talking it out but he says it's not helping.
Kind of looking for advice as to how he can put it back or right again.

Just working with the metaphor a little. I don't know if it's useful Is there something else he could do with the boxes other than close them? Is it possible to take things out of them to make them less full? Is there a safe room that they could be stored in. So it doesn't matter that they can't be closed? Is someone else able to take some of them?

This reminded me of an old thread I'd read. So I went back to look for it. But it was one of yours. So that explained why it was familiar. Is there a way to have another unveiling party? Or a letting go / letting remember ceremony?

This is the way he described It.
When they get these memories they are already boxed but he can't find the box now. There's nowhere to put it. The ISH asked me to talk tohim so I did but as I was the ish told my gf she had a mess to clean iphone so now she's working through them.
We shall see how it turns out.