SOLVED. YA Paranormal/ Horror. A family moves into a new home, they slowly begin to forget the existence of their youngest child, except the older sister who desperately tries to remind her parents. [s]

[Amie]

I read this around early 2000s, in a version translated in Korean. I'm pretty sure it was originally an English book, so I'm asking here.

I only remember the premise in the topic, and a few plot details relating to the conclusion. So spoilers ahead:

(view spoiler)[the older sister finds out that her missing and forgotten younger brother is in the basement--wrapped in some kind of slimey material?--with all the other forgotten children from previous families who lived there. Worse, the parents begin to forget the sister as well. She manages to remind her parents that they have two children, by holding up the younger brother's teddy bear and shouting something he used to say before (It was something along the lines of "the teddy bear can see me too!" The little brother said it after putting his own glasses on the bear, which was a big memory for the whole family, apparently.) The parents burst into tears and remembered both the sister and the younger brother--and they have a joyful reunion.

Everything seems back to normal, until the older sister talks with her best friend(?) and finds out that he forgot his own sibling, hinting that the horror is not over, but merely moved onto a different house. (hide spoiler)]

Really appreciate it if anybody can tell me what this book is!

[Becca]

Don't Forget Me! by R.L. Stine?

[Amie]

Yes that was it!!! thank you so much, Becca!