Bereft and bereaved are both past-tense and past-participle forms of the verb bereave, which means to leave desolate or alone, especially by death. Bereaved is appropriate in reference to someone who has lost a loved one by death. Bereft is better in reference to other types of losses. In this sense, bereft carries connotations that have been lost by the uninflected bereave, which almost always refers to the death of loved ones.
Examples
In these examples, bereaved refers to someone who has lost a loved one by death:
Despite the prevailing sorrow, visitors might gather around platters of food in a bereaved family’s home and celebrate a long life … [Forbes]
The way we treat our bereaved Armed Forces families speaks volumes about us as a nation. [Telegraph]
The government would also make a financial contribution to the families of the bereaved, to cover funeral expenses … [Herald Sun]
And in these sentences, bereft refers to other types of losses:
And how this city, for reasons that can never be completely explained, has been so bereft of sporting stars of the highest calibre. [Toronto Sun]
Having faded into obscurity at 40, bereft of even a single butler to send to the bread line, Fitzgerald wrote his most well-known essay from a rented room in a cheap hotel. [Wall Street Journal]
Short of money, the regime is also bereft of friends. [Financial Times]

