sorrowing vs bereaved

sorrowing is not a noun while bereaved is a noun.

Word	Noun	Adjective	Verb	Adverb
sorrowing	No	Yes	No	No
bereaved	Yes	Yes	No	No

As adjectives, sorrowing and bereaved are synonyms defined as:

Other synonyms of sorrowing include bereft, grief-stricken, grieving, mourning.

sorrowing (noun)	bereaved (noun)
	a person who has suffered the death of someone they loved

sorrowing (adjective)	bereaved (adjective)
sorrowful through loss or deprivation	sorrowful through loss or deprivation