The friend who can be silent with us in a moment of despair or confusion who can stay with us in an hour of grief and bereavement who can tolerate not knowing... not healing not curing... that is a friend who cares.
As a freelance writer I'd be asked to become an expert for various magazines on any subject whether food or wine or history or the life span of veterinarians. I was completely unschooled in any of these things.