I think I'm on solid ground to say this story is basically hurt/comfort. The first two tags label it as such and it was written for the HC_Bingo community. That's not a genre I'm naturally drawn to for some reason, but I suffer from traumatic nightmares myself, so I thought it would be interesting (even therapeutic) to see how that played out in fanfic. And boy does PipMer nail it. The disorientation, the warring unreality and hyperreality of the dreamscape, the need for any kind of distraction after – I found it a very believable picture of both being trapped in that kind of dream and also coming out of it.
I also really liked the way that PipMer recognizes this one night won't solve the whole problem. Sherlock will go on having these dreams, and life will go on. There is hurt and comfort but also crying babies (this is Johnlock with a divorced John with shared custody of Baby Girl Watson), and so the emphasis is not on never having to cope with the dreams again; it's on getting through just this one night. PipMer has a real gift for dialing down the angst, giving this drama-ridden fandom sories that are enjoyable and plausible without necessarily trying to solve those big questions, and this story is no different. I always enjoy that about her stories, and seeing her take on the aftereffects of HLV is a bit H/C (H/CCCCCCC) at a meta level for this fan.
Anyway, I enjoyed it. If you like Johnlock domesticity (this one is thoroughly PG), do give it a read.