Friendship grief is routinely underestimated. You may have known them longer than anyone in their family and still be at the back of the room.
Friendships that end without dying — drifts, fallings-out, estrangements — carry their own grief with no ritual at all.
You're allowed to take time off, to fall apart, to build your own memorial.
Tell their stories. Friends often hold the parts of a person nobody else witnessed.