A root in the Qenya Lexicon of the 1910s glossed “wither”, with derivatives having to do with withered things and winter (QL/40). In the contemporaneous Gnomish Lexicon the root was given as heth², but it is not clear whether this was intended to be a variant root or a replacement (GL/49). There are no signs of this root in Tolkien’s later writing, but I think it is worth salvaging as a Neo-Eldarin root ᴺ√KHES “wither” to salvage Gnomish and Early Qenya wither-words.
Early Primitive Elvish
heþe
root. HEÞE
heþe
root. HEÞE
heth·thed·’lon
noun. daisy
hese
root. brother or sister
hese
root. wither
niqi
root. white
pelek Reconstructed
root. axe
The root ᴱ√HESE appeared in the Qenya Lexicon of the 1910s with various derivatives having to do with siblings and blood relationships (QL/40). In the contemporaneous Gnomish Lexicon the root was given as heth¹ (GL/48), but it is not clear whether this was a replacement or a variant root for ᴱ√HESE.
Neo-Eldarin: I would adapt this as a Neo-Root ᴺ√KHETH “sibling, consanguinity” to serve as the basis for gender-neutral “sibling” words.