his memories were already slowly flicking and he especially had a clear flicker of the day in the snow dream abt waiting for that man's wife
on that day ibeom said something specific to him which he probably found really sentimental and important (like it probably hit him hard cus he in love yk) when they were in the dream of that man
after that in the chapter abt him remembering he said he just needs something like "when u try remember lyrics"
so in that case it'd be like it's at the tip of his tongue but he just needs a reminder to flip to switch and remember
and to remember he needed to know what ibeom said that day in the snow
which then helped him remember everything
i think anyway but that's how it makes sense to me
i did skipped few chapters. how was he able to remember him just from that one verse he said in the last chapter?