"Disenfranchised Grief" -- Losing a Friend Can Be as Devastating as Losing a Family Member

The so-called hierarchy of grief, a scale used to determine who is considered a more legitimate mourner than others, puts family members at the top. For this reason, the death of a close friend can feel shunted to the periphery and has been described as a disenfranchised grief...Friends are psychological kin, that is, you may even have a stronger bond with friends than people you are related to by birth or marriage. So when a friend dies, the psychological and emotional stress can be as bad as the death of kin.

The death of a friend can be as traumatic as losing a family member